diff --git a/java/res/drawable/btn_suggestion_lmp.xml b/java/res/color/emoji_tab_label_color_lxx.xml
similarity index 64%
copy from java/res/drawable/btn_suggestion_lmp.xml
copy to java/res/color/emoji_tab_label_color_lxx.xml
index 5c6b373..c2710d3 100644
--- a/java/res/drawable/btn_suggestion_lmp.xml
+++ b/java/res/color/emoji_tab_label_color_lxx.xml
@@ -18,10 +18,16 @@
 */
 -->
 
-<selector
-    xmlns:android="http://schemas.android.com/apk/res/android"
->
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+    <item
+        android:state_focused="true"
+        android:color="@color/key_text_color_holo" />
     <item
         android:state_pressed="true"
-        android:drawable="@color/suggested_word_background_selected_lmp" />
+        android:color="@color/key_text_color_holo" />
+    <item
+        android:state_selected="true"
+        android:color="@color/key_text_color_holo" />
+    <item
+        android:color="@color/key_text_inactive_color_lxx" />
 </selector>
diff --git a/java/res/drawable-hdpi/btn_keyboard_key_dark_normal_off_lmp.9.png b/java/res/drawable-hdpi/btn_keyboard_key_dark_normal_off_lxx.9.png
similarity index 100%
rename from java/res/drawable-hdpi/btn_keyboard_key_dark_normal_off_lmp.9.png
rename to java/res/drawable-hdpi/btn_keyboard_key_dark_normal_off_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-hdpi/btn_keyboard_key_dark_normal_on_lmp.9.png b/java/res/drawable-hdpi/btn_keyboard_key_dark_normal_on_lxx.9.png
similarity index 100%
rename from java/res/drawable-hdpi/btn_keyboard_key_dark_normal_on_lmp.9.png
rename to java/res/drawable-hdpi/btn_keyboard_key_dark_normal_on_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-hdpi/btn_keyboard_key_dark_pressed_off_lmp.9.png b/java/res/drawable-hdpi/btn_keyboard_key_dark_pressed_off_lxx.9.png
similarity index 100%
rename from java/res/drawable-hdpi/btn_keyboard_key_dark_pressed_off_lmp.9.png
rename to java/res/drawable-hdpi/btn_keyboard_key_dark_pressed_off_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-hdpi/btn_keyboard_key_dark_pressed_on_lmp.9.png b/java/res/drawable-hdpi/btn_keyboard_key_dark_pressed_on_lxx.9.png
similarity index 100%
rename from java/res/drawable-hdpi/btn_keyboard_key_dark_pressed_on_lmp.9.png
rename to java/res/drawable-hdpi/btn_keyboard_key_dark_pressed_on_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-hdpi/btn_keyboard_key_popup_selected_lmp.9.png b/java/res/drawable-hdpi/btn_keyboard_key_popup_selected_lxx.9.png
similarity index 100%
rename from java/res/drawable-hdpi/btn_keyboard_key_popup_selected_lmp.9.png
rename to java/res/drawable-hdpi/btn_keyboard_key_popup_selected_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-hdpi/keyboard_key_feedback_background_lmp.9.png b/java/res/drawable-hdpi/keyboard_key_feedback_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-hdpi/keyboard_key_feedback_background_lmp.9.png
rename to java/res/drawable-hdpi/keyboard_key_feedback_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-hdpi/keyboard_key_feedback_left_background_lmp.9.png b/java/res/drawable-hdpi/keyboard_key_feedback_left_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-hdpi/keyboard_key_feedback_left_background_lmp.9.png
rename to java/res/drawable-hdpi/keyboard_key_feedback_left_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-hdpi/keyboard_key_feedback_left_more_background_lmp.9.png b/java/res/drawable-hdpi/keyboard_key_feedback_left_more_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-hdpi/keyboard_key_feedback_left_more_background_lmp.9.png
rename to java/res/drawable-hdpi/keyboard_key_feedback_left_more_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-hdpi/keyboard_key_feedback_more_background_lmp.9.png b/java/res/drawable-hdpi/keyboard_key_feedback_more_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-hdpi/keyboard_key_feedback_more_background_lmp.9.png
rename to java/res/drawable-hdpi/keyboard_key_feedback_more_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-hdpi/keyboard_key_feedback_right_background_lmp.9.png b/java/res/drawable-hdpi/keyboard_key_feedback_right_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-hdpi/keyboard_key_feedback_right_background_lmp.9.png
rename to java/res/drawable-hdpi/keyboard_key_feedback_right_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-hdpi/keyboard_key_feedback_right_more_background_lmp.9.png b/java/res/drawable-hdpi/keyboard_key_feedback_right_more_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-hdpi/keyboard_key_feedback_right_more_background_lmp.9.png
rename to java/res/drawable-hdpi/keyboard_key_feedback_right_more_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-hdpi/keyboard_popup_panel_background_lmp.9.png b/java/res/drawable-hdpi/keyboard_popup_panel_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-hdpi/keyboard_popup_panel_background_lmp.9.png
rename to java/res/drawable-hdpi/keyboard_popup_panel_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-mdpi/btn_keyboard_key_dark_normal_off_lmp.9.png b/java/res/drawable-mdpi/btn_keyboard_key_dark_normal_off_lxx.9.png
similarity index 100%
rename from java/res/drawable-mdpi/btn_keyboard_key_dark_normal_off_lmp.9.png
rename to java/res/drawable-mdpi/btn_keyboard_key_dark_normal_off_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-mdpi/btn_keyboard_key_dark_normal_on_lmp.9.png b/java/res/drawable-mdpi/btn_keyboard_key_dark_normal_on_lxx.9.png
similarity index 100%
rename from java/res/drawable-mdpi/btn_keyboard_key_dark_normal_on_lmp.9.png
rename to java/res/drawable-mdpi/btn_keyboard_key_dark_normal_on_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-mdpi/btn_keyboard_key_dark_pressed_off_lmp.9.png b/java/res/drawable-mdpi/btn_keyboard_key_dark_pressed_off_lxx.9.png
similarity index 100%
rename from java/res/drawable-mdpi/btn_keyboard_key_dark_pressed_off_lmp.9.png
rename to java/res/drawable-mdpi/btn_keyboard_key_dark_pressed_off_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-mdpi/btn_keyboard_key_dark_pressed_on_lmp.9.png b/java/res/drawable-mdpi/btn_keyboard_key_dark_pressed_on_lxx.9.png
similarity index 100%
rename from java/res/drawable-mdpi/btn_keyboard_key_dark_pressed_on_lmp.9.png
rename to java/res/drawable-mdpi/btn_keyboard_key_dark_pressed_on_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-mdpi/btn_keyboard_key_popup_selected_lmp.9.png b/java/res/drawable-mdpi/btn_keyboard_key_popup_selected_lxx.9.png
similarity index 100%
rename from java/res/drawable-mdpi/btn_keyboard_key_popup_selected_lmp.9.png
rename to java/res/drawable-mdpi/btn_keyboard_key_popup_selected_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-mdpi/keyboard_key_feedback_background_lmp.9.png b/java/res/drawable-mdpi/keyboard_key_feedback_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-mdpi/keyboard_key_feedback_background_lmp.9.png
rename to java/res/drawable-mdpi/keyboard_key_feedback_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-mdpi/keyboard_key_feedback_left_background_lmp.9.png b/java/res/drawable-mdpi/keyboard_key_feedback_left_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-mdpi/keyboard_key_feedback_left_background_lmp.9.png
rename to java/res/drawable-mdpi/keyboard_key_feedback_left_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-mdpi/keyboard_key_feedback_left_more_background_lmp.9.png b/java/res/drawable-mdpi/keyboard_key_feedback_left_more_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-mdpi/keyboard_key_feedback_left_more_background_lmp.9.png
rename to java/res/drawable-mdpi/keyboard_key_feedback_left_more_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-mdpi/keyboard_key_feedback_more_background_lmp.9.png b/java/res/drawable-mdpi/keyboard_key_feedback_more_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-mdpi/keyboard_key_feedback_more_background_lmp.9.png
rename to java/res/drawable-mdpi/keyboard_key_feedback_more_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-mdpi/keyboard_key_feedback_right_background_lmp.9.png b/java/res/drawable-mdpi/keyboard_key_feedback_right_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-mdpi/keyboard_key_feedback_right_background_lmp.9.png
rename to java/res/drawable-mdpi/keyboard_key_feedback_right_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-mdpi/keyboard_key_feedback_right_more_background_lmp.9.png b/java/res/drawable-mdpi/keyboard_key_feedback_right_more_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-mdpi/keyboard_key_feedback_right_more_background_lmp.9.png
rename to java/res/drawable-mdpi/keyboard_key_feedback_right_more_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-mdpi/keyboard_popup_panel_background_lmp.9.png b/java/res/drawable-mdpi/keyboard_popup_panel_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-mdpi/keyboard_popup_panel_background_lmp.9.png
rename to java/res/drawable-mdpi/keyboard_popup_panel_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xhdpi/btn_keyboard_key_dark_normal_off_lmp.9.png b/java/res/drawable-xhdpi/btn_keyboard_key_dark_normal_off_lxx.9.png
similarity index 100%
rename from java/res/drawable-xhdpi/btn_keyboard_key_dark_normal_off_lmp.9.png
rename to java/res/drawable-xhdpi/btn_keyboard_key_dark_normal_off_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xhdpi/btn_keyboard_key_dark_normal_on_lmp.9.png b/java/res/drawable-xhdpi/btn_keyboard_key_dark_normal_on_lxx.9.png
similarity index 100%
rename from java/res/drawable-xhdpi/btn_keyboard_key_dark_normal_on_lmp.9.png
rename to java/res/drawable-xhdpi/btn_keyboard_key_dark_normal_on_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xhdpi/btn_keyboard_key_dark_pressed_off_lmp.9.png b/java/res/drawable-xhdpi/btn_keyboard_key_dark_pressed_off_lxx.9.png
similarity index 100%
rename from java/res/drawable-xhdpi/btn_keyboard_key_dark_pressed_off_lmp.9.png
rename to java/res/drawable-xhdpi/btn_keyboard_key_dark_pressed_off_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xhdpi/btn_keyboard_key_dark_pressed_on_lmp.9.png b/java/res/drawable-xhdpi/btn_keyboard_key_dark_pressed_on_lxx.9.png
similarity index 100%
rename from java/res/drawable-xhdpi/btn_keyboard_key_dark_pressed_on_lmp.9.png
rename to java/res/drawable-xhdpi/btn_keyboard_key_dark_pressed_on_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xhdpi/btn_keyboard_key_popup_selected_lmp.9.png b/java/res/drawable-xhdpi/btn_keyboard_key_popup_selected_lxx.9.png
similarity index 100%
rename from java/res/drawable-xhdpi/btn_keyboard_key_popup_selected_lmp.9.png
rename to java/res/drawable-xhdpi/btn_keyboard_key_popup_selected_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xhdpi/keyboard_key_feedback_background_lmp.9.png b/java/res/drawable-xhdpi/keyboard_key_feedback_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-xhdpi/keyboard_key_feedback_background_lmp.9.png
rename to java/res/drawable-xhdpi/keyboard_key_feedback_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xhdpi/keyboard_key_feedback_left_background_lmp.9.png b/java/res/drawable-xhdpi/keyboard_key_feedback_left_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-xhdpi/keyboard_key_feedback_left_background_lmp.9.png
rename to java/res/drawable-xhdpi/keyboard_key_feedback_left_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xhdpi/keyboard_key_feedback_left_more_background_lmp.9.png b/java/res/drawable-xhdpi/keyboard_key_feedback_left_more_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-xhdpi/keyboard_key_feedback_left_more_background_lmp.9.png
rename to java/res/drawable-xhdpi/keyboard_key_feedback_left_more_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xhdpi/keyboard_key_feedback_more_background_lmp.9.png b/java/res/drawable-xhdpi/keyboard_key_feedback_more_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-xhdpi/keyboard_key_feedback_more_background_lmp.9.png
rename to java/res/drawable-xhdpi/keyboard_key_feedback_more_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xhdpi/keyboard_key_feedback_right_background_lmp.9.png b/java/res/drawable-xhdpi/keyboard_key_feedback_right_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-xhdpi/keyboard_key_feedback_right_background_lmp.9.png
rename to java/res/drawable-xhdpi/keyboard_key_feedback_right_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xhdpi/keyboard_key_feedback_right_more_background_lmp.9.png b/java/res/drawable-xhdpi/keyboard_key_feedback_right_more_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-xhdpi/keyboard_key_feedback_right_more_background_lmp.9.png
rename to java/res/drawable-xhdpi/keyboard_key_feedback_right_more_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xhdpi/keyboard_popup_panel_background_lmp.9.png b/java/res/drawable-xhdpi/keyboard_popup_panel_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-xhdpi/keyboard_popup_panel_background_lmp.9.png
rename to java/res/drawable-xhdpi/keyboard_popup_panel_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xxhdpi/btn_keyboard_key_dark_normal_off_lmp.9.png b/java/res/drawable-xxhdpi/btn_keyboard_key_dark_normal_off_lxx.9.png
similarity index 100%
rename from java/res/drawable-xxhdpi/btn_keyboard_key_dark_normal_off_lmp.9.png
rename to java/res/drawable-xxhdpi/btn_keyboard_key_dark_normal_off_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xxhdpi/btn_keyboard_key_dark_normal_on_lmp.9.png b/java/res/drawable-xxhdpi/btn_keyboard_key_dark_normal_on_lxx.9.png
similarity index 100%
rename from java/res/drawable-xxhdpi/btn_keyboard_key_dark_normal_on_lmp.9.png
rename to java/res/drawable-xxhdpi/btn_keyboard_key_dark_normal_on_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xxhdpi/btn_keyboard_key_dark_pressed_off_lmp.9.png b/java/res/drawable-xxhdpi/btn_keyboard_key_dark_pressed_off_lxx.9.png
similarity index 100%
rename from java/res/drawable-xxhdpi/btn_keyboard_key_dark_pressed_off_lmp.9.png
rename to java/res/drawable-xxhdpi/btn_keyboard_key_dark_pressed_off_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xxhdpi/btn_keyboard_key_dark_pressed_on_lmp.9.png b/java/res/drawable-xxhdpi/btn_keyboard_key_dark_pressed_on_lxx.9.png
similarity index 100%
rename from java/res/drawable-xxhdpi/btn_keyboard_key_dark_pressed_on_lmp.9.png
rename to java/res/drawable-xxhdpi/btn_keyboard_key_dark_pressed_on_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xxhdpi/btn_keyboard_key_popup_selected_lmp.9.png b/java/res/drawable-xxhdpi/btn_keyboard_key_popup_selected_lxx.9.png
similarity index 100%
rename from java/res/drawable-xxhdpi/btn_keyboard_key_popup_selected_lmp.9.png
rename to java/res/drawable-xxhdpi/btn_keyboard_key_popup_selected_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xxhdpi/keyboard_key_feedback_background_lmp.9.png b/java/res/drawable-xxhdpi/keyboard_key_feedback_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-xxhdpi/keyboard_key_feedback_background_lmp.9.png
rename to java/res/drawable-xxhdpi/keyboard_key_feedback_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xxhdpi/keyboard_key_feedback_left_background_lmp.9.png b/java/res/drawable-xxhdpi/keyboard_key_feedback_left_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-xxhdpi/keyboard_key_feedback_left_background_lmp.9.png
rename to java/res/drawable-xxhdpi/keyboard_key_feedback_left_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xxhdpi/keyboard_key_feedback_left_more_background_lmp.9.png b/java/res/drawable-xxhdpi/keyboard_key_feedback_left_more_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-xxhdpi/keyboard_key_feedback_left_more_background_lmp.9.png
rename to java/res/drawable-xxhdpi/keyboard_key_feedback_left_more_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xxhdpi/keyboard_key_feedback_more_background_lmp.9.png b/java/res/drawable-xxhdpi/keyboard_key_feedback_more_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-xxhdpi/keyboard_key_feedback_more_background_lmp.9.png
rename to java/res/drawable-xxhdpi/keyboard_key_feedback_more_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xxhdpi/keyboard_key_feedback_right_background_lmp.9.png b/java/res/drawable-xxhdpi/keyboard_key_feedback_right_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-xxhdpi/keyboard_key_feedback_right_background_lmp.9.png
rename to java/res/drawable-xxhdpi/keyboard_key_feedback_right_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xxhdpi/keyboard_key_feedback_right_more_background_lmp.9.png b/java/res/drawable-xxhdpi/keyboard_key_feedback_right_more_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-xxhdpi/keyboard_key_feedback_right_more_background_lmp.9.png
rename to java/res/drawable-xxhdpi/keyboard_key_feedback_right_more_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable-xxhdpi/keyboard_popup_panel_background_lmp.9.png b/java/res/drawable-xxhdpi/keyboard_popup_panel_background_lxx.9.png
similarity index 100%
rename from java/res/drawable-xxhdpi/keyboard_popup_panel_background_lmp.9.png
rename to java/res/drawable-xxhdpi/keyboard_popup_panel_background_lxx.9.png
Binary files differ
diff --git a/java/res/drawable/btn_keyboard_key_functional_lmp.xml b/java/res/drawable/btn_keyboard_key_functional_lxx.xml
similarity index 86%
rename from java/res/drawable/btn_keyboard_key_functional_lmp.xml
rename to java/res/drawable/btn_keyboard_key_functional_lxx.xml
index 57a8355..fc6f98d 100644
--- a/java/res/drawable/btn_keyboard_key_functional_lmp.xml
+++ b/java/res/drawable/btn_keyboard_key_functional_lxx.xml
@@ -17,6 +17,6 @@
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
     <!-- Functional keys. -->
     <item android:state_pressed="true"
-          android:drawable="@color/key_background_pressed_lmp" />
-    <item android:drawable="@color/key_background_lmp" />
+          android:drawable="@color/key_background_pressed_lxx" />
+    <item android:drawable="@color/key_background_lxx" />
 </selector>
diff --git a/java/res/drawable/btn_keyboard_key_ics.xml b/java/res/drawable/btn_keyboard_key_ics.xml
index 9db0eee..af14cd5 100644
--- a/java/res/drawable/btn_keyboard_key_ics.xml
+++ b/java/res/drawable/btn_keyboard_key_ics.xml
@@ -15,12 +15,6 @@
 -->
 
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
-    <!-- Functional keys. -->
-    <item android:state_single="true" android:state_pressed="true"
-          android:drawable="@drawable/btn_keyboard_key_dark_pressed_ics" />
-    <item android:state_single="true"
-          android:drawable="@drawable/btn_keyboard_key_dark_normal_holo" />
-
     <!-- Action keys. -->
     <item android:state_active="true" android:state_pressed="true"
           android:drawable="@drawable/btn_keyboard_key_dark_pressed_ics" />
diff --git a/java/res/drawable/btn_keyboard_key_klp.xml b/java/res/drawable/btn_keyboard_key_klp.xml
index 500e3ea..56c295f 100644
--- a/java/res/drawable/btn_keyboard_key_klp.xml
+++ b/java/res/drawable/btn_keyboard_key_klp.xml
@@ -15,12 +15,6 @@
 -->
 
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
-    <!-- Functional keys. -->
-    <item android:state_single="true" android:state_pressed="true"
-          android:drawable="@drawable/btn_keyboard_key_dark_pressed_klp" />
-    <item android:state_single="true"
-          android:drawable="@drawable/btn_keyboard_key_dark_normal_holo" />
-
     <!-- Action keys. -->
     <item android:state_active="true" android:state_pressed="true"
           android:drawable="@drawable/btn_keyboard_key_dark_pressed_klp" />
diff --git a/java/res/drawable/btn_keyboard_key_lmp.xml b/java/res/drawable/btn_keyboard_key_lxx.xml
similarity index 72%
rename from java/res/drawable/btn_keyboard_key_lmp.xml
rename to java/res/drawable/btn_keyboard_key_lxx.xml
index 4aaafb5..fc19a0b 100644
--- a/java/res/drawable/btn_keyboard_key_lmp.xml
+++ b/java/res/drawable/btn_keyboard_key_lxx.xml
@@ -15,34 +15,28 @@
 -->
 
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
-    <!-- Functional keys. -->
-    <item android:state_single="true" android:state_pressed="true"
-          android:drawable="@color/key_background_pressed_lmp" />
-    <item android:state_single="true"
-          android:drawable="@color/key_background_lmp" />
-
     <!-- Action keys. -->
     <item android:state_active="true" android:state_pressed="true"
-          android:drawable="@color/key_background_pressed_lmp" />
+          android:drawable="@color/key_background_pressed_lxx" />
     <item android:state_active="true"
-          android:drawable="@color/key_background_lmp" />
+          android:drawable="@color/key_background_lxx" />
 
     <!-- Toggle keys. Use checkable/checked state. -->
     <item android:state_checkable="true" android:state_checked="true" android:state_pressed="true"
-          android:drawable="@drawable/btn_keyboard_key_dark_pressed_on_lmp" />
+          android:drawable="@drawable/btn_keyboard_key_dark_pressed_on_lxx" />
     <item android:state_checkable="true" android:state_pressed="true"
-          android:drawable="@drawable/btn_keyboard_key_dark_pressed_off_lmp" />
+          android:drawable="@drawable/btn_keyboard_key_dark_pressed_off_lxx" />
     <item android:state_checkable="true" android:state_checked="true"
-          android:drawable="@drawable/btn_keyboard_key_dark_normal_on_lmp" />
+          android:drawable="@drawable/btn_keyboard_key_dark_normal_on_lxx" />
     <item android:state_checkable="true"
-          android:drawable="@drawable/btn_keyboard_key_dark_normal_off_lmp" />
+          android:drawable="@drawable/btn_keyboard_key_dark_normal_off_lxx" />
 
     <!-- Empty background keys. -->
     <item android:state_empty="true"
-          android:drawable="@color/key_background_lmp" />
+          android:drawable="@color/key_background_lxx" />
 
     <!-- Normal keys. -->
     <item android:state_pressed="true"
-          android:drawable="@color/key_background_pressed_lmp" />
-    <item android:drawable="@color/key_background_lmp" />
+          android:drawable="@color/key_background_pressed_lxx" />
+    <item android:drawable="@color/key_background_lxx" />
 </selector>
diff --git a/java/res/drawable/btn_keyboard_key_popup_lmp.xml b/java/res/drawable/btn_keyboard_key_popup_lxx.xml
similarity index 98%
rename from java/res/drawable/btn_keyboard_key_popup_lmp.xml
rename to java/res/drawable/btn_keyboard_key_popup_lxx.xml
index ebedaea..7daebc8 100644
--- a/java/res/drawable/btn_keyboard_key_popup_lmp.xml
+++ b/java/res/drawable/btn_keyboard_key_popup_lxx.xml
@@ -16,6 +16,6 @@
 
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
     <item android:state_pressed="true"
-          android:drawable="@drawable/btn_keyboard_key_popup_selected_lmp" />
+          android:drawable="@drawable/btn_keyboard_key_popup_selected_lxx" />
     <item android:drawable="@android:color/transparent" />
 </selector>
diff --git a/java/res/drawable/btn_keyboard_spacebar_lmp.xml b/java/res/drawable/btn_keyboard_spacebar_lxx.xml
similarity index 86%
rename from java/res/drawable/btn_keyboard_spacebar_lmp.xml
rename to java/res/drawable/btn_keyboard_spacebar_lxx.xml
index d05972f..10d04a8 100644
--- a/java/res/drawable/btn_keyboard_spacebar_lmp.xml
+++ b/java/res/drawable/btn_keyboard_spacebar_lxx.xml
@@ -16,6 +16,6 @@
 
 <selector xmlns:android="http://schemas.android.com/apk/res/android">
     <item android:state_pressed="true"
-          android:drawable="@color/key_background_pressed_lmp" />
-    <item android:drawable="@color/key_background_lmp" />
+          android:drawable="@color/key_background_pressed_lxx" />
+    <item android:drawable="@color/key_background_lxx" />
 </selector>
diff --git a/java/res/drawable/btn_suggestion_lmp.xml b/java/res/drawable/btn_suggestion_lxx.xml
similarity index 98%
rename from java/res/drawable/btn_suggestion_lmp.xml
rename to java/res/drawable/btn_suggestion_lxx.xml
index 5c6b373..c73e1f7 100644
--- a/java/res/drawable/btn_suggestion_lmp.xml
+++ b/java/res/drawable/btn_suggestion_lxx.xml
@@ -23,5 +23,5 @@
 >
     <item
         android:state_pressed="true"
-        android:drawable="@color/suggested_word_background_selected_lmp" />
+        android:drawable="@color/suggested_word_background_selected_lxx" />
 </selector>
diff --git a/java/res/drawable/keyboard_key_feedback_lmp.xml b/java/res/drawable/keyboard_key_feedback_lxx.xml
similarity index 92%
rename from java/res/drawable/keyboard_key_feedback_lmp.xml
rename to java/res/drawable/keyboard_key_feedback_lxx.xml
index cdbe64c..2abbc90 100644
--- a/java/res/drawable/keyboard_key_feedback_lmp.xml
+++ b/java/res/drawable/keyboard_key_feedback_lxx.xml
@@ -20,17 +20,17 @@
 >
     <!-- Left edge -->
     <item latin:state_left_edge="true" latin:state_has_morekeys="true"
-          android:drawable="@drawable/keyboard_key_feedback_left_more_background_lmp" />
+          android:drawable="@drawable/keyboard_key_feedback_left_more_background_lxx" />
     <item latin:state_left_edge="true"
-          android:drawable="@drawable/keyboard_key_feedback_left_background_lmp" />
+          android:drawable="@drawable/keyboard_key_feedback_left_background_lxx" />
 
     <!-- Right edge -->
     <item latin:state_right_edge="true" latin:state_has_morekeys="true"
-          android:drawable="@drawable/keyboard_key_feedback_right_more_background_lmp" />
+          android:drawable="@drawable/keyboard_key_feedback_right_more_background_lxx" />
     <item latin:state_right_edge="true"
-          android:drawable="@drawable/keyboard_key_feedback_right_background_lmp" />
+          android:drawable="@drawable/keyboard_key_feedback_right_background_lxx" />
 
     <item latin:state_has_morekeys="true"
-          android:drawable="@drawable/keyboard_key_feedback_more_background_lmp" />
-    <item android:drawable="@drawable/keyboard_key_feedback_background_lmp" />
+          android:drawable="@drawable/keyboard_key_feedback_more_background_lxx" />
+    <item android:drawable="@drawable/keyboard_key_feedback_background_lxx" />
 </selector>
diff --git a/java/res/layout/emoji_keyboard_page.xml b/java/res/layout/emoji_keyboard_page.xml
index 9afad36..0d10861 100644
--- a/java/res/layout/emoji_keyboard_page.xml
+++ b/java/res/layout/emoji_keyboard_page.xml
@@ -18,7 +18,7 @@
 */
 -->
 
-<com.android.inputmethod.keyboard.internal.EmojiPageKeyboardView
+<com.android.inputmethod.keyboard.emoji.EmojiPageKeyboardView
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/emoji_keyboard_page"
     android:layoutDirection="ltr"
diff --git a/java/res/layout/emoji_palettes_view.xml b/java/res/layout/emoji_palettes_view.xml
index 552a474..7618871 100644
--- a/java/res/layout/emoji_palettes_view.xml
+++ b/java/res/layout/emoji_palettes_view.xml
@@ -18,7 +18,7 @@
 */
 -->
 
-<com.android.inputmethod.keyboard.EmojiPalettesView
+<com.android.inputmethod.keyboard.emoji.EmojiPalettesView
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/emoji_keyboard_view"
     android:orientation="vertical"
@@ -78,7 +78,7 @@
         android:id="@+id/emoji_keyboard_pager"
         android:layout_width="match_parent"
         android:layout_height="wrap_content" />
-    <com.android.inputmethod.keyboard.EmojiCategoryPageIndicatorView
+    <com.android.inputmethod.keyboard.emoji.EmojiCategoryPageIndicatorView
         android:id="@+id/emoji_category_page_id_view"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
@@ -109,4 +109,4 @@
             android:gravity="center"
             android:layout_height="match_parent" />
     </LinearLayout>
-</com.android.inputmethod.keyboard.EmojiPalettesView>
+</com.android.inputmethod.keyboard.emoji.EmojiPalettesView>
diff --git a/java/res/values/attrs.xml b/java/res/values/attrs.xml
index 769a1d9..79cc139 100644
--- a/java/res/values/attrs.xml
+++ b/java/res/values/attrs.xml
@@ -41,13 +41,16 @@
     </declare-styleable>
 
     <declare-styleable name="KeyboardView">
-        <!-- Image for the key. This image needs to be a {@link StateListDrawable}, with the
-             following possible states: normal, pressed, checkable, checkable+pressed,
+        <!-- Background image for the key. This image needs to be a {@link StateListDrawable},
+             with the following possible states: normal, pressed, checkable, checkable+pressed,
              checkable+checked, checkable+checked+pressed. -->
         <attr name="keyBackground" format="reference" />
-        <!-- Image for the functional key used in Emoji layout. -->
-        <attr name="keyBackgroundEmojiFunctional" format="reference" />
-
+        <!-- Background image for the functional key. This image needs to be a
+             {@link StateListDrawable}, with the following possible states: normal, pressed. -->
+        <attr name="functionalKeyBackground" format="reference" />
+        <!-- Background image for the spacebar.  This image needs to be a
+             {@link StateListDrawable}, with the following possible states: normal, pressed. -->
+        <attr name="spacebarBackground" format="reference" />
         <!-- Horizontal padding of left/right aligned key label to the edge of the key. -->
         <attr name="keyLabelHorizontalPadding" format="dimension" />
         <!-- Right padding of hint letter to the edge of the key.-->
@@ -76,8 +79,6 @@
         <attr name="languageOnSpacebarTextColor" format="color" />
         <attr name="languageOnSpacebarTextShadowRadius" format="float" />
         <attr name="languageOnSpacebarTextShadowColor" format="color" />
-        <!-- Background image for the spacebar. -->
-        <attr name="spacebarBackground" format="reference" />
         <!-- Fadeout animator for spacebar language label. -->
         <attr name="languageOnSpacebarFinalAlpha" format="integer" />
         <attr name="languageOnSpacebarFadeoutAnimator" format="reference" />
diff --git a/java/res/values/colors.xml b/java/res/values/colors.xml
index db9a27a..60b5cdf 100644
--- a/java/res/values/colors.xml
+++ b/java/res/values/colors.xml
@@ -39,18 +39,18 @@
     <color name="typed_word_color_klp">#D8F0F0F0</color>
     <color name="suggested_word_color_klp">#B2F0F0F0</color>
     <color name="highlight_translucent_color_klp">#99E0E0E0</color>
-    <!-- Color resources for LMP theme. Base color = F0F0F0 -->
-    <color name="key_text_inactive_color_lmp">#808184</color>
-    <color name="key_hint_letter_color_lmp">#808184</color>
-    <color name="highlight_color_lmp">#7FCAC3</color>
-    <color name="typed_word_color_lmp">#D87FCAC3</color>
-    <color name="suggested_word_color_lmp">#B27FCAC3</color>
-    <color name="highlight_translucent_color_lmp">#997FCAC3</color>
-    <color name="keyboard_background_lmp">#384248</color>
-    <color name="key_background_lmp">#384248</color>
-    <color name="key_background_pressed_lmp">#546872</color>
-    <color name="suggestions_strip_background_lmp">#263238</color>
-    <color name="suggested_word_background_selected_lmp">#384248</color>
+    <!-- Color resources for LXX theme. Base color = F0F0F0 -->
+    <color name="key_text_inactive_color_lxx">#808184</color>
+    <color name="key_hint_letter_color_lxx">#808184</color>
+    <color name="highlight_color_lxx">#7FCAC3</color>
+    <color name="typed_word_color_lxx">#D87FCAC3</color>
+    <color name="suggested_word_color_lxx">#B27FCAC3</color>
+    <color name="highlight_translucent_color_lxx">#997FCAC3</color>
+    <color name="keyboard_background_lxx">#384248</color>
+    <color name="key_background_lxx">#384248</color>
+    <color name="key_background_pressed_lxx">#546872</color>
+    <color name="suggestions_strip_background_lxx">#263238</color>
+    <color name="suggested_word_background_selected_lxx">#384248</color>
     <!-- Color resources for setup wizard and tutorial -->
     <color name="setup_background">#FFEBEBEB</color>
     <color name="setup_text_dark">#FF707070</color>
diff --git a/java/res/values/config-common.xml b/java/res/values/config-common.xml
index 1962c0d..ad27ab4 100644
--- a/java/res/values/config-common.xml
+++ b/java/res/values/config-common.xml
@@ -133,7 +133,7 @@
     <integer name="config_gesture_trail_shadow_ratio">-1</integer>
 
     <!-- Common configuration of Emoji keyboard -->
-    <dimen name="config_emoji_category_page_id_height">3dp</dimen>
+    <dimen name="config_emoji_category_page_id_height">2dp</dimen>
 
     <!-- Inset used in Accessibility mode to avoid accidental key presses when a finger slides off the screen. -->
     <dimen name="config_accessibility_edge_slop">8dp</dimen>
diff --git a/java/res/values/keyboard-icons-lmp.xml b/java/res/values/keyboard-icons-lxx.xml
similarity index 98%
rename from java/res/values/keyboard-icons-lmp.xml
rename to java/res/values/keyboard-icons-lxx.xml
index 39e0fe3..ea4b6e6 100644
--- a/java/res/values/keyboard-icons-lmp.xml
+++ b/java/res/values/keyboard-icons-lxx.xml
@@ -19,7 +19,7 @@
 -->
 
 <resources xmlns:android="http://schemas.android.com/apk/res/android">
-    <style name="KeyboardIcons.LMP">
+    <style name="KeyboardIcons.LXX">
         <!-- Keyboard icons -->
         <item name="iconShiftKey">@drawable/sym_keyboard_shift_holo_dark</item>
         <item name="iconDeleteKey">@drawable/sym_keyboard_delete_holo_dark</item>
diff --git a/java/res/values/themes-common.xml b/java/res/values/themes-common.xml
index 76abb10..df26fb3 100644
--- a/java/res/values/themes-common.xml
+++ b/java/res/values/themes-common.xml
@@ -109,12 +109,7 @@
     <style name="KeyPreviewTextView" />
     <!-- Though {@link EmojiPalettesView} doesn't extend {@link KeyboardView}, some views inside it,
          for instance delete button, need themed {@link KeyboardView} attributes. -->
-    <style
-        name="EmojiPalettesView"
-        parent="KeyboardView"
-    >
-        <item name="emojiTabLabelColor">@color/emoji_tab_label_color_holo</item>
-    </style>
+    <style name="EmojiPalettesView" />
     <style name="MoreKeysKeyboard" />
     <style
         name="MoreKeysKeyboardView"
diff --git a/java/res/values/themes-ics.xml b/java/res/values/themes-ics.xml
index d7943ee..560cfc5 100644
--- a/java/res/values/themes-ics.xml
+++ b/java/res/values/themes-ics.xml
@@ -48,6 +48,8 @@
     >
         <item name="android:background">@drawable/keyboard_background_holo</item>
         <item name="keyBackground">@drawable/btn_keyboard_key_ics</item>
+        <item name="functionalKeyBackground">@drawable/btn_keyboard_key_functional_ics</item>
+        <item name="spacebarBackground">@drawable/btn_keyboard_spacebar_ics</item>
         <item name="keyTypeface">bold</item>
         <item name="keyTextColor">@color/key_text_color_holo</item>
         <item name="keyTextInactivatedColor">@color/key_text_inactivated_color_holo</item>
@@ -73,7 +75,6 @@
         <item name="languageOnSpacebarTextColor">@color/spacebar_text_color_holo</item>
         <item name="languageOnSpacebarTextShadowRadius">1.0</item>
         <item name="languageOnSpacebarTextShadowColor">@color/spacebar_text_shadow_color_holo</item>
-        <item name="spacebarBackground">@drawable/btn_keyboard_spacebar_ics</item>
     </style>
     <style
         name="KeyPreviewTextView.ICS"
@@ -85,9 +86,8 @@
          for instance delete button, need themed {@link KeyboardView} attributes. -->
     <style
         name="EmojiPalettesView.ICS"
-        parent="KeyboardView.ICS"
+        parent="MainKeyboardView.ICS"
     >
-        <item name="keyBackgroundEmojiFunctional">@drawable/btn_keyboard_key_functional_ics</item>
         <item name="emojiTabLabelColor">@color/emoji_tab_label_color_holo</item>
     </style>
     <style
diff --git a/java/res/values/themes-klp.xml b/java/res/values/themes-klp.xml
index 13500fe..453e5cb 100644
--- a/java/res/values/themes-klp.xml
+++ b/java/res/values/themes-klp.xml
@@ -48,6 +48,8 @@
     >
         <item name="android:background">@drawable/keyboard_background_holo</item>
         <item name="keyBackground">@drawable/btn_keyboard_key_klp</item>
+        <item name="functionalKeyBackground">@drawable/btn_keyboard_key_functional_klp</item>
+        <item name="spacebarBackground">@drawable/btn_keyboard_spacebar_klp</item>
         <item name="keyTypeface">bold</item>
         <item name="keyTextColor">@color/key_text_color_holo</item>
         <item name="keyTextInactivatedColor">@color/key_text_inactivated_color_holo</item>
@@ -73,7 +75,6 @@
         <item name="languageOnSpacebarTextColor">@color/spacebar_text_color_holo</item>
         <item name="languageOnSpacebarTextShadowRadius">1.0</item>
         <item name="languageOnSpacebarTextShadowColor">@color/spacebar_text_shadow_color_holo</item>
-        <item name="spacebarBackground">@drawable/btn_keyboard_spacebar_klp</item>
     </style>
     <style
         name="KeyPreviewTextView.KLP"
@@ -85,9 +86,8 @@
          for instance delete button, need themed {@link KeyboardView} attributes. -->
     <style
         name="EmojiPalettesView.KLP"
-        parent="KeyboardView.KLP"
+        parent="MainKeyboardView.KLP"
     >
-        <item name="keyBackgroundEmojiFunctional">@drawable/btn_keyboard_key_functional_klp</item>
         <item name="emojiTabLabelColor">@color/emoji_tab_label_color_holo</item>
     </style>
     <style
diff --git a/java/res/values/themes-lmp.xml b/java/res/values/themes-lxx.xml
similarity index 76%
rename from java/res/values/themes-lmp.xml
rename to java/res/values/themes-lxx.xml
index c05190b..4f3ee80 100644
--- a/java/res/values/themes-lmp.xml
+++ b/java/res/values/themes-lxx.xml
@@ -19,19 +19,19 @@
 -->
 
 <resources xmlns:android="http://schemas.android.com/apk/res/android">
-    <style name="KeyboardTheme.LMP" parent="KeyboardIcons.LMP">
-        <item name="keyboardStyle">@style/Keyboard.LMP</item>
-        <item name="keyboardViewStyle">@style/KeyboardView.LMP</item>
-        <item name="mainKeyboardViewStyle">@style/MainKeyboardView.LMP</item>
-        <item name="keyPreviewTextViewStyle">@style/KeyPreviewTextView.LMP</item>
-        <item name="emojiPalettesViewStyle">@style/EmojiPalettesView.LMP</item>
-        <item name="moreKeysKeyboardStyle">@style/MoreKeysKeyboard.LMP</item>
-        <item name="moreKeysKeyboardViewStyle">@style/MoreKeysKeyboardView.LMP</item>
-        <item name="suggestionStripViewStyle">@style/SuggestionStripView.LMP</item>
-        <item name="suggestionWordStyle">@style/SuggestionWord.LMP</item>
+    <style name="KeyboardTheme.LXX" parent="KeyboardIcons.LXX">
+        <item name="keyboardStyle">@style/Keyboard.LXX</item>
+        <item name="keyboardViewStyle">@style/KeyboardView.LXX</item>
+        <item name="mainKeyboardViewStyle">@style/MainKeyboardView.LXX</item>
+        <item name="keyPreviewTextViewStyle">@style/KeyPreviewTextView.LXX</item>
+        <item name="emojiPalettesViewStyle">@style/EmojiPalettesView.LXX</item>
+        <item name="moreKeysKeyboardStyle">@style/MoreKeysKeyboard.LXX</item>
+        <item name="moreKeysKeyboardViewStyle">@style/MoreKeysKeyboardView.LXX</item>
+        <item name="suggestionStripViewStyle">@style/SuggestionStripView.LXX</item>
+        <item name="suggestionWordStyle">@style/SuggestionWord.LXX</item>
     </style>
     <style
-        name="Keyboard.LMP"
+        name="Keyboard.LXX"
         parent="Keyboard"
     >
         <!-- This should be aligned with KeyboardSwitcher.KEYBOARD_THEMES[] -->
@@ -43,56 +43,56 @@
         <item name="touchPositionCorrectionData">@array/touch_position_correction_data_holo</item>
     </style>
     <style
-        name="KeyboardView.LMP"
+        name="KeyboardView.LXX"
         parent="KeyboardView"
     >
-        <item name="android:background">@color/keyboard_background_lmp</item>
-        <item name="keyBackground">@drawable/btn_keyboard_key_lmp</item>
+        <item name="android:background">@color/keyboard_background_lxx</item>
+        <item name="keyBackground">@drawable/btn_keyboard_key_lxx</item>
+        <item name="functionalKeyBackground">@drawable/btn_keyboard_key_functional_lxx</item>
+        <item name="spacebarBackground">@drawable/btn_keyboard_spacebar_lxx</item>
         <item name="keyTypeface">bold</item>
         <item name="keyTextColor">@color/key_text_color_holo</item>
-        <item name="keyTextInactivatedColor">@color/key_text_inactive_color_lmp</item>
-        <item name="keyHintLetterColor">@color/key_hint_letter_color_lmp</item>
-        <item name="keyHintLabelColor">@color/key_text_inactive_color_lmp</item>
-        <item name="keyShiftedLetterHintInactivatedColor">@color/key_text_inactive_color_lmp</item>
+        <item name="keyTextInactivatedColor">@color/key_text_inactive_color_lxx</item>
+        <item name="keyHintLetterColor">@color/key_hint_letter_color_lxx</item>
+        <item name="keyHintLabelColor">@color/key_text_inactive_color_lxx</item>
+        <item name="keyShiftedLetterHintInactivatedColor">@color/key_text_inactive_color_lxx</item>
         <item name="keyShiftedLetterHintActivatedColor">@color/key_text_color_holo</item>
         <item name="keyPreviewTextColor">@color/key_text_color_holo</item>
         <!-- A negative value to disable key text shadow layer. -->
         <item name="keyTextShadowRadius">-1.0</item>
     </style>
     <style
-        name="MainKeyboardView.LMP"
-        parent="KeyboardView.LMP"
+        name="MainKeyboardView.LXX"
+        parent="KeyboardView.LXX"
     >
         <item name="keyPreviewOffset">@dimen/config_key_preview_offset_holo</item>
-        <item name="gestureFloatingPreviewTextColor">@color/highlight_color_lmp</item>
+        <item name="gestureFloatingPreviewTextColor">@color/highlight_color_lxx</item>
         <item name="gestureFloatingPreviewColor">@color/gesture_floating_preview_color_holo</item>
-        <item name="gestureTrailColor">@color/highlight_color_lmp</item>
-        <item name="slidingKeyInputPreviewColor">@color/highlight_translucent_color_lmp</item>
+        <item name="gestureTrailColor">@color/highlight_color_lxx</item>
+        <item name="slidingKeyInputPreviewColor">@color/highlight_translucent_color_lxx</item>
         <item name="autoCorrectionSpacebarLedEnabled">false</item>
         <item name="autoCorrectionSpacebarLedIcon">@drawable/sym_keyboard_space_led_holo</item>
-        <item name="languageOnSpacebarTextColor">@color/key_text_inactive_color_lmp</item>
+        <item name="languageOnSpacebarTextColor">@color/key_text_inactive_color_lxx</item>
         <!-- A negative value to disable text shadow layer. -->
         <item name="languageOnSpacebarTextShadowRadius">-1.0</item>
-        <item name="spacebarBackground">@drawable/btn_keyboard_spacebar_lmp</item>
     </style>
     <style
-        name="KeyPreviewTextView.LMP"
+        name="KeyPreviewTextView.LXX"
         parent="KeyPreviewTextView"
     >
-        <item name="android:background">@drawable/keyboard_key_feedback_lmp</item>
+        <item name="android:background">@drawable/keyboard_key_feedback_lxx</item>
     </style>
     <!-- Though {@link EmojiPalettesView} doesn't extend {@link KeyboardView}, some views inside it,
          for instance delete button, need themed {@link KeyboardView} attributes. -->
     <style
-        name="EmojiPalettesView.LMP"
-        parent="KeyboardView.LMP"
+        name="EmojiPalettesView.LXX"
+        parent="MainKeyboardView.LXX"
     >
-        <item name="keyBackgroundEmojiFunctional">@drawable/btn_keyboard_key_functional_lmp</item>
-        <item name="emojiTabLabelColor">@color/emoji_tab_label_color_holo</item>
+        <item name="emojiTabLabelColor">@color/emoji_tab_label_color_lxx</item>
     </style>
     <style
-        name="MoreKeysKeyboard.LMP"
-        parent="Keyboard.LMP"
+        name="MoreKeysKeyboard.LXX"
+        parent="Keyboard.LXX"
     >
         <item name="keyboardTopPadding">0%p</item>
         <item name="keyboardBottomPadding">0%p</item>
@@ -100,17 +100,17 @@
         <item name="touchPositionCorrectionData">@null</item>
     </style>
     <style
-        name="MoreKeysKeyboardView.LMP"
-        parent="KeyboardView.LMP"
+        name="MoreKeysKeyboardView.LXX"
+        parent="KeyboardView.LXX"
     >
-        <item name="android:background">@drawable/keyboard_popup_panel_background_lmp</item>
-        <item name="keyBackground">@drawable/btn_keyboard_key_popup_lmp</item>
+        <item name="android:background">@drawable/keyboard_popup_panel_background_lxx</item>
+        <item name="keyBackground">@drawable/btn_keyboard_key_popup_lxx</item>
         <item name="keyTypeface">normal</item>
         <item name="verticalCorrection">@dimen/config_more_keys_keyboard_vertical_correction_holo</item>
     </style>
     <style
-        name="SuggestionStripView.LMP"
-        parent="KeyboardView.LMP"
+        name="SuggestionStripView.LXX"
+        parent="KeyboardView.LXX"
     >
         <item name="suggestionsCountInStrip">@integer/config_suggestions_count_in_strip</item>
         <item name="centerSuggestionPercentile">@fraction/config_center_suggestion_percentile</item>
@@ -118,17 +118,17 @@
         <item name="minMoreSuggestionsWidth">@fraction/config_min_more_suggestions_width</item>
         <item name="android:background">@drawable/keyboard_suggest_strip_holo</item>
         <item name="suggestionStripOptions">autoCorrectBold|validTypedWordBold</item>
-        <item name="colorValidTypedWord">@color/typed_word_color_lmp</item>
-        <item name="colorTypedWord">@color/typed_word_color_lmp</item>
-        <item name="colorAutoCorrect">@color/highlight_color_lmp</item>
-        <item name="colorSuggested">@color/suggested_word_color_lmp</item>
+        <item name="colorValidTypedWord">@color/typed_word_color_lxx</item>
+        <item name="colorTypedWord">@color/typed_word_color_lxx</item>
+        <item name="colorAutoCorrect">@color/highlight_color_lxx</item>
+        <item name="colorSuggested">@color/suggested_word_color_lxx</item>
         <item name="alphaObsoleted">70%</item>
     </style>
     <style
-        name="SuggestionWord.LMP"
+        name="SuggestionWord.LXX"
         parent="SuggestionWord"
     >
-        <item name="android:background">@drawable/btn_suggestion_lmp</item>
-        <item name="android:textColor">@color/highlight_color_lmp</item>
+        <item name="android:background">@drawable/btn_suggestion_lxx</item>
+        <item name="android:textColor">@color/highlight_color_lxx</item>
     </style>
 </resources>
diff --git a/java/src/com/android/inputmethod/event/CombinerChain.java b/java/src/com/android/inputmethod/event/CombinerChain.java
index 990f7de..9e7f04d 100644
--- a/java/src/com/android/inputmethod/event/CombinerChain.java
+++ b/java/src/com/android/inputmethod/event/CombinerChain.java
@@ -56,18 +56,20 @@
      *
      * The combiner chain takes events as inputs and outputs code points and combining state.
      * For example, if the input language is Japanese, the combining chain will typically perform
-     * kana conversion.
+     * kana conversion. This takes a string for initial text, taken to be present before the
+     * cursor: we'll start after this.
      *
+     * @param initialText The text that has already been combined so far.
      * @param combinerList A list of combiners to be applied in order.
      */
-    public CombinerChain(final Combiner... combinerList) {
+    public CombinerChain(final String initialText, final Combiner... combinerList) {
         mCombiners = CollectionUtils.newArrayList();
         // The dead key combiner is always active, and always first
         mCombiners.add(new DeadKeyCombiner());
         for (final Combiner combiner : combinerList) {
             mCombiners.add(combiner);
         }
-        mCombinedText = new StringBuilder();
+        mCombinedText = new StringBuilder(initialText);
         mStateFeedback = new SpannableStringBuilder();
     }
 
diff --git a/java/src/com/android/inputmethod/event/MyanmarReordering.java b/java/src/com/android/inputmethod/event/MyanmarReordering.java
index 27b8c14..da0228b 100644
--- a/java/src/com/android/inputmethod/event/MyanmarReordering.java
+++ b/java/src/com/android/inputmethod/event/MyanmarReordering.java
@@ -207,9 +207,33 @@
                 return clearAndGetResultingEvent(newEvent);
             }
         } else if (Constants.CODE_DELETE == newEvent.mKeyCode) {
-            if (mCurrentEvents.size() > 0) {
-                mCurrentEvents.remove(mCurrentEvents.size() - 1);
-                return null;
+            final Event lastEvent = getLastEvent();
+            final int eventSize = mCurrentEvents.size();
+            if (null != lastEvent) {
+                if (VOWEL_E == lastEvent.mCodePoint) {
+                    // We have a VOWEL_E at the end. There are four cases.
+                    // - The vowel is the only code point in the buffer. Remove it.
+                    // - The vowel is preceded by a ZWNJ. Remove both vowel E and ZWNJ.
+                    // - The vowel is preceded by a consonant/medial, remove the consonant/medial.
+                    // - In all other cases, it's strange, so just remove the last code point.
+                    if (eventSize <= 1) {
+                        mCurrentEvents.clear();
+                    } else { // eventSize >= 2
+                        final int previousCodePoint = mCurrentEvents.get(eventSize - 2).mCodePoint;
+                        if (previousCodePoint == ZERO_WIDTH_NON_JOINER) {
+                            mCurrentEvents.remove(eventSize - 1);
+                            mCurrentEvents.remove(eventSize - 2);
+                        } else if (isConsonantOrMedial(previousCodePoint)) {
+                            mCurrentEvents.remove(eventSize - 2);
+                        } else {
+                            mCurrentEvents.remove(eventSize - 1);
+                        }
+                    }
+                    return null;
+                } else if (eventSize > 0) {
+                    mCurrentEvents.remove(eventSize - 1);
+                    return null;
+                }
             }
         }
         // This character is not part of the combining scheme, so we should reset everything.
diff --git a/java/src/com/android/inputmethod/keyboard/EmojiPalettesView.java b/java/src/com/android/inputmethod/keyboard/EmojiPalettesView.java
deleted file mode 100644
index d8b5758..0000000
--- a/java/src/com/android/inputmethod/keyboard/EmojiPalettesView.java
+++ /dev/null
@@ -1,974 +0,0 @@
-/*
- * Copyright (C) 2013 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package com.android.inputmethod.keyboard;
-
-import static com.android.inputmethod.latin.Constants.NOT_A_COORDINATE;
-
-import android.content.Context;
-import android.content.SharedPreferences;
-import android.content.res.ColorStateList;
-import android.content.res.Resources;
-import android.content.res.TypedArray;
-import android.graphics.Color;
-import android.graphics.Rect;
-import android.os.Build;
-import android.os.CountDownTimer;
-import android.preference.PreferenceManager;
-import android.support.v4.view.PagerAdapter;
-import android.support.v4.view.ViewPager;
-import android.util.AttributeSet;
-import android.util.Log;
-import android.util.Pair;
-import android.util.SparseArray;
-import android.util.TypedValue;
-import android.view.LayoutInflater;
-import android.view.MotionEvent;
-import android.view.View;
-import android.view.ViewGroup;
-import android.widget.ImageView;
-import android.widget.LinearLayout;
-import android.widget.TabHost;
-import android.widget.TabHost.OnTabChangeListener;
-import android.widget.TextView;
-
-import com.android.inputmethod.keyboard.internal.DynamicGridKeyboard;
-import com.android.inputmethod.keyboard.internal.EmojiLayoutParams;
-import com.android.inputmethod.keyboard.internal.EmojiPageKeyboardView;
-import com.android.inputmethod.keyboard.internal.KeyDrawParams;
-import com.android.inputmethod.keyboard.internal.KeyVisualAttributes;
-import com.android.inputmethod.latin.Constants;
-import com.android.inputmethod.latin.R;
-import com.android.inputmethod.latin.SubtypeSwitcher;
-import com.android.inputmethod.latin.settings.Settings;
-import com.android.inputmethod.latin.utils.CollectionUtils;
-import com.android.inputmethod.latin.utils.ResourceUtils;
-
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.HashMap;
-import java.util.List;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.TimeUnit;
-
-/**
- * View class to implement Emoji palettes.
- * The Emoji keyboard consists of group of views {@link R.layout#emoji_palettes_view}.
- * <ol>
- * <li> Emoji category tabs.
- * <li> Delete button.
- * <li> Emoji keyboard pages that can be scrolled by swiping horizontally or by selecting a tab.
- * <li> Back to main keyboard button and enter button.
- * </ol>
- * Because of the above reasons, this class doesn't extend {@link KeyboardView}.
- */
-public final class EmojiPalettesView extends LinearLayout implements OnTabChangeListener,
-        ViewPager.OnPageChangeListener, View.OnClickListener, View.OnTouchListener,
-        EmojiPageKeyboardView.OnKeyEventListener {
-    static final String TAG = EmojiPalettesView.class.getSimpleName();
-    private static final boolean DEBUG_PAGER = false;
-    private final int mKeyBackgroundId;
-    private final int mEmojiFunctionalKeyBackgroundId;
-    private final ColorStateList mTabLabelColor;
-    private final DeleteKeyOnTouchListener mDeleteKeyOnTouchListener;
-    private EmojiPalettesAdapter mEmojiPalettesAdapter;
-    private final EmojiLayoutParams mEmojiLayoutParams;
-
-    private TextView mAlphabetKeyLeft;
-    private TextView mAlphabetKeyRight;
-    private TabHost mTabHost;
-    private ViewPager mEmojiPager;
-    private int mCurrentPagerPosition = 0;
-    private EmojiCategoryPageIndicatorView mEmojiCategoryPageIndicatorView;
-
-    private KeyboardActionListener mKeyboardActionListener = KeyboardActionListener.EMPTY_LISTENER;
-
-    private static final int CATEGORY_ID_UNSPECIFIED = -1;
-    public static final int CATEGORY_ID_RECENTS = 0;
-    public static final int CATEGORY_ID_PEOPLE = 1;
-    public static final int CATEGORY_ID_OBJECTS = 2;
-    public static final int CATEGORY_ID_NATURE = 3;
-    public static final int CATEGORY_ID_PLACES = 4;
-    public static final int CATEGORY_ID_SYMBOLS = 5;
-    public static final int CATEGORY_ID_EMOTICONS = 6;
-
-    private static class CategoryProperties {
-        public int mCategoryId;
-        public int mPageCount;
-        public CategoryProperties(final int categoryId, final int pageCount) {
-            mCategoryId = categoryId;
-            mPageCount = pageCount;
-        }
-    }
-
-    private static class EmojiCategory {
-        private static final String[] sCategoryName = {
-                "recents",
-                "people",
-                "objects",
-                "nature",
-                "places",
-                "symbols",
-                "emoticons" };
-        private static final int[] sCategoryIcon = {
-                R.drawable.ic_emoji_recent_light,
-                R.drawable.ic_emoji_people_light,
-                R.drawable.ic_emoji_objects_light,
-                R.drawable.ic_emoji_nature_light,
-                R.drawable.ic_emoji_places_light,
-                R.drawable.ic_emoji_symbols_light,
-                0 };
-        private static final String[] sCategoryLabel =
-                { null, null, null, null, null, null, ":-)" };
-        private static final int[] sAccessibilityDescriptionResourceIdsForCategories = {
-                R.string.spoken_descrption_emoji_category_recents,
-                R.string.spoken_descrption_emoji_category_people,
-                R.string.spoken_descrption_emoji_category_objects,
-                R.string.spoken_descrption_emoji_category_nature,
-                R.string.spoken_descrption_emoji_category_places,
-                R.string.spoken_descrption_emoji_category_symbols,
-                R.string.spoken_descrption_emoji_category_emoticons };
-        private static final int[] sCategoryElementId = {
-                KeyboardId.ELEMENT_EMOJI_RECENTS,
-                KeyboardId.ELEMENT_EMOJI_CATEGORY1,
-                KeyboardId.ELEMENT_EMOJI_CATEGORY2,
-                KeyboardId.ELEMENT_EMOJI_CATEGORY3,
-                KeyboardId.ELEMENT_EMOJI_CATEGORY4,
-                KeyboardId.ELEMENT_EMOJI_CATEGORY5,
-                KeyboardId.ELEMENT_EMOJI_CATEGORY6 };
-        private final SharedPreferences mPrefs;
-        private final Resources mRes;
-        private final int mMaxPageKeyCount;
-        private final KeyboardLayoutSet mLayoutSet;
-        private final HashMap<String, Integer> mCategoryNameToIdMap = CollectionUtils.newHashMap();
-        private final ArrayList<CategoryProperties> mShownCategories =
-                CollectionUtils.newArrayList();
-        private final ConcurrentHashMap<Long, DynamicGridKeyboard>
-                mCategoryKeyboardMap = new ConcurrentHashMap<Long, DynamicGridKeyboard>();
-
-        private int mCurrentCategoryId = CATEGORY_ID_UNSPECIFIED;
-        private int mCurrentCategoryPageId = 0;
-
-        public EmojiCategory(final SharedPreferences prefs, final Resources res,
-                final KeyboardLayoutSet layoutSet) {
-            mPrefs = prefs;
-            mRes = res;
-            mMaxPageKeyCount = res.getInteger(R.integer.config_emoji_keyboard_max_page_key_count);
-            mLayoutSet = layoutSet;
-            for (int i = 0; i < sCategoryName.length; ++i) {
-                mCategoryNameToIdMap.put(sCategoryName[i], i);
-            }
-            addShownCategoryId(CATEGORY_ID_RECENTS);
-            if (Build.VERSION.SDK_INT > Build.VERSION_CODES.JELLY_BEAN_MR2
-                    || android.os.Build.VERSION.CODENAME.equalsIgnoreCase("KeyLimePie")
-                    || android.os.Build.VERSION.CODENAME.equalsIgnoreCase("KitKat")) {
-                addShownCategoryId(CATEGORY_ID_PEOPLE);
-                addShownCategoryId(CATEGORY_ID_OBJECTS);
-                addShownCategoryId(CATEGORY_ID_NATURE);
-                addShownCategoryId(CATEGORY_ID_PLACES);
-                mCurrentCategoryId =
-                        Settings.readLastShownEmojiCategoryId(mPrefs, CATEGORY_ID_PEOPLE);
-            } else {
-                mCurrentCategoryId =
-                        Settings.readLastShownEmojiCategoryId(mPrefs, CATEGORY_ID_SYMBOLS);
-            }
-            addShownCategoryId(CATEGORY_ID_SYMBOLS);
-            addShownCategoryId(CATEGORY_ID_EMOTICONS);
-            getKeyboard(CATEGORY_ID_RECENTS, 0 /* cagetoryPageId */)
-                    .loadRecentKeys(mCategoryKeyboardMap.values());
-        }
-
-        private void addShownCategoryId(final int categoryId) {
-            // Load a keyboard of categoryId
-            getKeyboard(categoryId, 0 /* cagetoryPageId */);
-            final CategoryProperties properties =
-                    new CategoryProperties(categoryId, getCategoryPageCount(categoryId));
-            mShownCategories.add(properties);
-        }
-
-        public String getCategoryName(final int categoryId, final int categoryPageId) {
-            return sCategoryName[categoryId] + "-" + categoryPageId;
-        }
-
-        public int getCategoryId(final String name) {
-            final String[] strings = name.split("-");
-            return mCategoryNameToIdMap.get(strings[0]);
-        }
-
-        public int getCategoryIcon(final int categoryId) {
-            return sCategoryIcon[categoryId];
-        }
-
-        public String getCategoryLabel(final int categoryId) {
-            return sCategoryLabel[categoryId];
-        }
-
-        public String getAccessibilityDescription(final int categoryId) {
-            return mRes.getString(sAccessibilityDescriptionResourceIdsForCategories[categoryId]);
-        }
-
-        public ArrayList<CategoryProperties> getShownCategories() {
-            return mShownCategories;
-        }
-
-        public int getCurrentCategoryId() {
-            return mCurrentCategoryId;
-        }
-
-        public int getCurrentCategoryPageSize() {
-            return getCategoryPageSize(mCurrentCategoryId);
-        }
-
-        public int getCategoryPageSize(final int categoryId) {
-            for (final CategoryProperties prop : mShownCategories) {
-                if (prop.mCategoryId == categoryId) {
-                    return prop.mPageCount;
-                }
-            }
-            Log.w(TAG, "Invalid category id: " + categoryId);
-            // Should not reach here.
-            return 0;
-        }
-
-        public void setCurrentCategoryId(final int categoryId) {
-            mCurrentCategoryId = categoryId;
-            Settings.writeLastShownEmojiCategoryId(mPrefs, categoryId);
-        }
-
-        public void setCurrentCategoryPageId(final int id) {
-            mCurrentCategoryPageId = id;
-        }
-
-        public int getCurrentCategoryPageId() {
-            return mCurrentCategoryPageId;
-        }
-
-        public void saveLastTypedCategoryPage() {
-            Settings.writeLastTypedEmojiCategoryPageId(
-                    mPrefs, mCurrentCategoryId, mCurrentCategoryPageId);
-        }
-
-        public boolean isInRecentTab() {
-            return mCurrentCategoryId == CATEGORY_ID_RECENTS;
-        }
-
-        public int getTabIdFromCategoryId(final int categoryId) {
-            for (int i = 0; i < mShownCategories.size(); ++i) {
-                if (mShownCategories.get(i).mCategoryId == categoryId) {
-                    return i;
-                }
-            }
-            Log.w(TAG, "categoryId not found: " + categoryId);
-            return 0;
-        }
-
-        // Returns the view pager's page position for the categoryId
-        public int getPageIdFromCategoryId(final int categoryId) {
-            final int lastSavedCategoryPageId =
-                    Settings.readLastTypedEmojiCategoryPageId(mPrefs, categoryId);
-            int sum = 0;
-            for (int i = 0; i < mShownCategories.size(); ++i) {
-                final CategoryProperties props = mShownCategories.get(i);
-                if (props.mCategoryId == categoryId) {
-                    return sum + lastSavedCategoryPageId;
-                }
-                sum += props.mPageCount;
-            }
-            Log.w(TAG, "categoryId not found: " + categoryId);
-            return 0;
-        }
-
-        public int getRecentTabId() {
-            return getTabIdFromCategoryId(CATEGORY_ID_RECENTS);
-        }
-
-        private int getCategoryPageCount(final int categoryId) {
-            final Keyboard keyboard = mLayoutSet.getKeyboard(sCategoryElementId[categoryId]);
-            return (keyboard.getSortedKeys().size() - 1) / mMaxPageKeyCount + 1;
-        }
-
-        // Returns a pair of the category id and the category page id from the view pager's page
-        // position. The category page id is numbered in each category. And the view page position
-        // is the position of the current shown page in the view pager which contains all pages of
-        // all categories.
-        public Pair<Integer, Integer> getCategoryIdAndPageIdFromPagePosition(final int position) {
-            int sum = 0;
-            for (final CategoryProperties properties : mShownCategories) {
-                final int temp = sum;
-                sum += properties.mPageCount;
-                if (sum > position) {
-                    return new Pair<Integer, Integer>(properties.mCategoryId, position - temp);
-                }
-            }
-            return null;
-        }
-
-        // Returns a keyboard from the view pager's page position.
-        public DynamicGridKeyboard getKeyboardFromPagePosition(final int position) {
-            final Pair<Integer, Integer> categoryAndId =
-                    getCategoryIdAndPageIdFromPagePosition(position);
-            if (categoryAndId != null) {
-                return getKeyboard(categoryAndId.first, categoryAndId.second);
-            }
-            return null;
-        }
-
-        private static final Long getCategoryKeyboardMapKey(final int categoryId, final int id) {
-            return (((long) categoryId) << Constants.MAX_INT_BIT_COUNT) | id;
-        }
-
-        public DynamicGridKeyboard getKeyboard(final int categoryId, final int id) {
-            synchronized (mCategoryKeyboardMap) {
-                final Long categotyKeyboardMapKey = getCategoryKeyboardMapKey(categoryId, id);
-                if (mCategoryKeyboardMap.containsKey(categotyKeyboardMapKey)) {
-                    return mCategoryKeyboardMap.get(categotyKeyboardMapKey);
-                }
-
-                if (categoryId == CATEGORY_ID_RECENTS) {
-                    final DynamicGridKeyboard kbd = new DynamicGridKeyboard(mPrefs,
-                            mLayoutSet.getKeyboard(KeyboardId.ELEMENT_EMOJI_RECENTS),
-                            mMaxPageKeyCount, categoryId);
-                    mCategoryKeyboardMap.put(categotyKeyboardMapKey, kbd);
-                    return kbd;
-                }
-
-                final Keyboard keyboard = mLayoutSet.getKeyboard(sCategoryElementId[categoryId]);
-                final Key[][] sortedKeys = sortKeysIntoPages(
-                        keyboard.getSortedKeys(), mMaxPageKeyCount);
-                for (int pageId = 0; pageId < sortedKeys.length; ++pageId) {
-                    final DynamicGridKeyboard tempKeyboard = new DynamicGridKeyboard(mPrefs,
-                            mLayoutSet.getKeyboard(KeyboardId.ELEMENT_EMOJI_RECENTS),
-                            mMaxPageKeyCount, categoryId);
-                    for (final Key emojiKey : sortedKeys[pageId]) {
-                        if (emojiKey == null) {
-                            break;
-                        }
-                        tempKeyboard.addKeyLast(emojiKey);
-                    }
-                    mCategoryKeyboardMap.put(
-                            getCategoryKeyboardMapKey(categoryId, pageId), tempKeyboard);
-                }
-                return mCategoryKeyboardMap.get(categotyKeyboardMapKey);
-            }
-        }
-
-        public int getTotalPageCountOfAllCategories() {
-            int sum = 0;
-            for (CategoryProperties properties : mShownCategories) {
-                sum += properties.mPageCount;
-            }
-            return sum;
-        }
-
-        private static Comparator<Key> EMOJI_KEY_COMPARATOR = new Comparator<Key>() {
-            @Override
-            public int compare(final Key lhs, final Key rhs) {
-                final Rect lHitBox = lhs.getHitBox();
-                final Rect rHitBox = rhs.getHitBox();
-                if (lHitBox.top < rHitBox.top) {
-                    return -1;
-                } else if (lHitBox.top > rHitBox.top) {
-                    return 1;
-                }
-                if (lHitBox.left < rHitBox.left) {
-                    return -1;
-                } else if (lHitBox.left > rHitBox.left) {
-                    return 1;
-                }
-                if (lhs.getCode() == rhs.getCode()) {
-                    return 0;
-                }
-                return lhs.getCode() < rhs.getCode() ? -1 : 1;
-            }
-        };
-
-        private static Key[][] sortKeysIntoPages(final List<Key> inKeys, final int maxPageCount) {
-            final ArrayList<Key> keys = CollectionUtils.newArrayList(inKeys);
-            Collections.sort(keys, EMOJI_KEY_COMPARATOR);
-            final int pageCount = (keys.size() - 1) / maxPageCount + 1;
-            final Key[][] retval = new Key[pageCount][maxPageCount];
-            for (int i = 0; i < keys.size(); ++i) {
-                retval[i / maxPageCount][i % maxPageCount] = keys.get(i);
-            }
-            return retval;
-        }
-    }
-
-    private final EmojiCategory mEmojiCategory;
-
-    public EmojiPalettesView(final Context context, final AttributeSet attrs) {
-        this(context, attrs, R.attr.emojiPalettesViewStyle);
-    }
-
-    public EmojiPalettesView(final Context context, final AttributeSet attrs, final int defStyle) {
-        super(context, attrs, defStyle);
-        final TypedArray keyboardViewAttr = context.obtainStyledAttributes(attrs,
-                R.styleable.KeyboardView, defStyle, R.style.KeyboardView);
-        mKeyBackgroundId = keyboardViewAttr.getResourceId(
-                R.styleable.KeyboardView_keyBackground, 0);
-        mEmojiFunctionalKeyBackgroundId = keyboardViewAttr.getResourceId(
-                R.styleable.KeyboardView_keyBackgroundEmojiFunctional, 0);
-        keyboardViewAttr.recycle();
-        final TypedArray emojiPalettesViewAttr = context.obtainStyledAttributes(attrs,
-                R.styleable.EmojiPalettesView, defStyle, R.style.EmojiPalettesView);
-        mTabLabelColor = emojiPalettesViewAttr.getColorStateList(
-                R.styleable.EmojiPalettesView_emojiTabLabelColor);
-        emojiPalettesViewAttr.recycle();
-        final KeyboardLayoutSet.Builder builder = new KeyboardLayoutSet.Builder(
-                context, null /* editorInfo */);
-        final Resources res = context.getResources();
-        mEmojiLayoutParams = new EmojiLayoutParams(res);
-        builder.setSubtype(SubtypeSwitcher.getInstance().getEmojiSubtype());
-        builder.setKeyboardGeometry(ResourceUtils.getDefaultKeyboardWidth(res),
-                mEmojiLayoutParams.mEmojiKeyboardHeight);
-        builder.setOptions(false /* shortcutImeEnabled */, false /* showsVoiceInputKey */,
-                false /* languageSwitchKeyEnabled */);
-        mEmojiCategory = new EmojiCategory(PreferenceManager.getDefaultSharedPreferences(context),
-                context.getResources(), builder.build());
-        mDeleteKeyOnTouchListener = new DeleteKeyOnTouchListener(context);
-    }
-
-    @Override
-    protected void onMeasure(final int widthMeasureSpec, final int heightMeasureSpec) {
-        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
-        final Resources res = getContext().getResources();
-        // The main keyboard expands to the entire this {@link KeyboardView}.
-        final int width = ResourceUtils.getDefaultKeyboardWidth(res)
-                + getPaddingLeft() + getPaddingRight();
-        final int height = ResourceUtils.getDefaultKeyboardHeight(res)
-                + res.getDimensionPixelSize(R.dimen.config_suggestions_strip_height)
-                + getPaddingTop() + getPaddingBottom();
-        setMeasuredDimension(width, height);
-    }
-
-    private void addTab(final TabHost host, final int categoryId) {
-        final String tabId = mEmojiCategory.getCategoryName(categoryId, 0 /* categoryPageId */);
-        final TabHost.TabSpec tspec = host.newTabSpec(tabId);
-        tspec.setContent(R.id.emoji_keyboard_dummy);
-        if (mEmojiCategory.getCategoryIcon(categoryId) != 0) {
-            final ImageView iconView = (ImageView)LayoutInflater.from(getContext()).inflate(
-                    R.layout.emoji_keyboard_tab_icon, null);
-            iconView.setImageResource(mEmojiCategory.getCategoryIcon(categoryId));
-            iconView.setContentDescription(mEmojiCategory.getAccessibilityDescription(categoryId));
-            tspec.setIndicator(iconView);
-        }
-        if (mEmojiCategory.getCategoryLabel(categoryId) != null) {
-            final TextView textView = (TextView)LayoutInflater.from(getContext()).inflate(
-                    R.layout.emoji_keyboard_tab_label, null);
-            textView.setText(mEmojiCategory.getCategoryLabel(categoryId));
-            textView.setContentDescription(mEmojiCategory.getAccessibilityDescription(categoryId));
-            textView.setTextColor(mTabLabelColor);
-            tspec.setIndicator(textView);
-        }
-        host.addTab(tspec);
-    }
-
-    @Override
-    protected void onFinishInflate() {
-        mTabHost = (TabHost)findViewById(R.id.emoji_category_tabhost);
-        mTabHost.setup();
-        for (final CategoryProperties properties : mEmojiCategory.getShownCategories()) {
-            addTab(mTabHost, properties.mCategoryId);
-        }
-        mTabHost.setOnTabChangedListener(this);
-        mTabHost.getTabWidget().setStripEnabled(true);
-
-        mEmojiPalettesAdapter = new EmojiPalettesAdapter(mEmojiCategory, this);
-
-        mEmojiPager = (ViewPager)findViewById(R.id.emoji_keyboard_pager);
-        mEmojiPager.setAdapter(mEmojiPalettesAdapter);
-        mEmojiPager.setOnPageChangeListener(this);
-        mEmojiPager.setOffscreenPageLimit(0);
-        mEmojiPager.setPersistentDrawingCache(PERSISTENT_NO_CACHE);
-        mEmojiLayoutParams.setPagerProperties(mEmojiPager);
-
-        mEmojiCategoryPageIndicatorView =
-                (EmojiCategoryPageIndicatorView)findViewById(R.id.emoji_category_page_id_view);
-        mEmojiLayoutParams.setCategoryPageIdViewProperties(mEmojiCategoryPageIndicatorView);
-
-        setCurrentCategoryId(mEmojiCategory.getCurrentCategoryId(), true /* force */);
-
-        final LinearLayout actionBar = (LinearLayout)findViewById(R.id.emoji_action_bar);
-        mEmojiLayoutParams.setActionBarProperties(actionBar);
-
-        // deleteKey depends only on OnTouchListener.
-        final ImageView deleteKey = (ImageView)findViewById(R.id.emoji_keyboard_delete);
-        deleteKey.setTag(Constants.CODE_DELETE);
-        deleteKey.setOnTouchListener(mDeleteKeyOnTouchListener);
-
-        // {@link #mAlphabetKeyLeft}, {@link #mAlphabetKeyRight, and spaceKey depend on
-        // {@link View.OnClickListener} as well as {@link View.OnTouchListener}.
-        // {@link View.OnTouchListener} is used as the trigger of key-press, while
-        // {@link View.OnClickListener} is used as the trigger of key-release which does not occur
-        // if the event is canceled by moving off the finger from the view.
-        // The text on alphabet keys are set at
-        // {@link #startEmojiPalettes(String,int,float,Typeface)}.
-        mAlphabetKeyLeft = (TextView)findViewById(R.id.emoji_keyboard_alphabet_left);
-        mAlphabetKeyLeft.setBackgroundResource(mEmojiFunctionalKeyBackgroundId);
-        mAlphabetKeyLeft.setTag(Constants.CODE_ALPHA_FROM_EMOJI);
-        mAlphabetKeyLeft.setOnTouchListener(this);
-        mAlphabetKeyLeft.setOnClickListener(this);
-        mAlphabetKeyRight = (TextView)findViewById(R.id.emoji_keyboard_alphabet_right);
-        mAlphabetKeyRight.setBackgroundResource(mEmojiFunctionalKeyBackgroundId);
-        mAlphabetKeyRight.setTag(Constants.CODE_ALPHA_FROM_EMOJI);
-        mAlphabetKeyRight.setOnTouchListener(this);
-        mAlphabetKeyRight.setOnClickListener(this);
-        final ImageView spaceKey = (ImageView)findViewById(R.id.emoji_keyboard_space);
-        spaceKey.setBackgroundResource(mKeyBackgroundId);
-        spaceKey.setTag(Constants.CODE_SPACE);
-        spaceKey.setOnTouchListener(this);
-        spaceKey.setOnClickListener(this);
-        mEmojiLayoutParams.setKeyProperties(spaceKey);
-    }
-
-    @Override
-    public boolean dispatchTouchEvent(final MotionEvent ev) {
-        // Add here to the stack trace to nail down the {@link IllegalArgumentException} exception
-        // in MotionEvent that sporadically happens.
-        // TODO: Remove this override method once the issue has been addressed.
-        return super.dispatchTouchEvent(ev);
-    }
-
-    @Override
-    public void onTabChanged(final String tabId) {
-        final int categoryId = mEmojiCategory.getCategoryId(tabId);
-        setCurrentCategoryId(categoryId, false /* force */);
-        updateEmojiCategoryPageIdView();
-    }
-
-    @Override
-    public void onPageSelected(final int position) {
-        final Pair<Integer, Integer> newPos =
-                mEmojiCategory.getCategoryIdAndPageIdFromPagePosition(position);
-        setCurrentCategoryId(newPos.first /* categoryId */, false /* force */);
-        mEmojiCategory.setCurrentCategoryPageId(newPos.second /* categoryPageId */);
-        updateEmojiCategoryPageIdView();
-        mCurrentPagerPosition = position;
-    }
-
-    @Override
-    public void onPageScrollStateChanged(final int state) {
-        // Ignore this message. Only want the actual page selected.
-    }
-
-    @Override
-    public void onPageScrolled(final int position, final float positionOffset,
-            final int positionOffsetPixels) {
-        mEmojiPalettesAdapter.onPageScrolled();
-        final Pair<Integer, Integer> newPos =
-                mEmojiCategory.getCategoryIdAndPageIdFromPagePosition(position);
-        final int newCategoryId = newPos.first;
-        final int newCategorySize = mEmojiCategory.getCategoryPageSize(newCategoryId);
-        final int currentCategoryId = mEmojiCategory.getCurrentCategoryId();
-        final int currentCategoryPageId = mEmojiCategory.getCurrentCategoryPageId();
-        final int currentCategorySize = mEmojiCategory.getCurrentCategoryPageSize();
-        if (newCategoryId == currentCategoryId) {
-            mEmojiCategoryPageIndicatorView.setCategoryPageId(
-                    newCategorySize, newPos.second, positionOffset);
-        } else if (newCategoryId > currentCategoryId) {
-            mEmojiCategoryPageIndicatorView.setCategoryPageId(
-                    currentCategorySize, currentCategoryPageId, positionOffset);
-        } else if (newCategoryId < currentCategoryId) {
-            mEmojiCategoryPageIndicatorView.setCategoryPageId(
-                    currentCategorySize, currentCategoryPageId, positionOffset - 1);
-        }
-    }
-
-    /**
-     * Called from {@link EmojiPageKeyboardView} through {@link android.view.View.OnTouchListener}
-     * interface to handle touch events from View-based elements such as the space bar.
-     * Note that this method is used only for observing {@link MotionEvent#ACTION_DOWN} to trigger
-     * {@link KeyboardActionListener#onPressKey}. {@link KeyboardActionListener#onReleaseKey} will
-     * be covered by {@link #onClick} as long as the event is not canceled.
-     */
-    @Override
-    public boolean onTouch(final View v, final MotionEvent event) {
-        if (event.getActionMasked() != MotionEvent.ACTION_DOWN) {
-            return false;
-        }
-        final Object tag = v.getTag();
-        if (!(tag instanceof Integer)) {
-            return false;
-        }
-        final int code = (Integer) tag;
-        mKeyboardActionListener.onPressKey(
-                code, 0 /* repeatCount */, true /* isSinglePointer */);
-        // It's important to return false here. Otherwise, {@link #onClick} and touch-down visual
-        // feedback stop working.
-        return false;
-    }
-
-    /**
-     * Called from {@link EmojiPageKeyboardView} through {@link android.view.View.OnClickListener}
-     * interface to handle non-canceled touch-up events from View-based elements such as the space
-     * bar.
-     */
-    @Override
-    public void onClick(View v) {
-        final Object tag = v.getTag();
-        if (!(tag instanceof Integer)) {
-            return;
-        }
-        final int code = (Integer) tag;
-        mKeyboardActionListener.onCodeInput(code, NOT_A_COORDINATE, NOT_A_COORDINATE,
-                false /* isKeyRepeat */);
-        mKeyboardActionListener.onReleaseKey(code, false /* withSliding */);
-    }
-
-    /**
-     * Called from {@link EmojiPageKeyboardView} through
-     * {@link com.android.inputmethod.keyboard.internal.EmojiPageKeyboardView.OnKeyEventListener}
-     * interface to handle touch events from non-View-based elements such as Emoji buttons.
-     */
-    @Override
-    public void onPressKey(final Key key) {
-        final int code = key.getCode();
-        mKeyboardActionListener.onPressKey(code, 0 /* repeatCount */, true /* isSinglePointer */);
-    }
-
-    /**
-     * Called from {@link EmojiPageKeyboardView} through
-     * {@link com.android.inputmethod.keyboard.internal.EmojiPageKeyboardView.OnKeyEventListener}
-     * interface to handle touch events from non-View-based elements such as Emoji buttons.
-     */
-    @Override
-    public void onReleaseKey(final Key key) {
-        mEmojiPalettesAdapter.addRecentKey(key);
-        mEmojiCategory.saveLastTypedCategoryPage();
-        final int code = key.getCode();
-        if (code == Constants.CODE_OUTPUT_TEXT) {
-            mKeyboardActionListener.onTextInput(key.getOutputText());
-        } else {
-            mKeyboardActionListener.onCodeInput(code, NOT_A_COORDINATE, NOT_A_COORDINATE,
-                    false /* isKeyRepeat */);
-        }
-        mKeyboardActionListener.onReleaseKey(code, false /* withSliding */);
-    }
-
-    public void setHardwareAcceleratedDrawingEnabled(final boolean enabled) {
-        if (!enabled) return;
-        // TODO: Should use LAYER_TYPE_SOFTWARE when hardware acceleration is off?
-        setLayerType(LAYER_TYPE_HARDWARE, null);
-    }
-
-    private static void setupAlphabetKey(final TextView alphabetKey, final String label,
-            final KeyDrawParams params) {
-        alphabetKey.setText(label);
-        alphabetKey.setTextColor(params.mTextColor);
-        alphabetKey.setTextSize(TypedValue.COMPLEX_UNIT_PX, params.mLabelSize);
-        alphabetKey.setTypeface(params.mTypeface);
-    }
-
-    public void startEmojiPalettes(final String switchToAlphaLabel,
-            final KeyVisualAttributes keyVisualAttr) {
-        if (DEBUG_PAGER) {
-            Log.d(TAG, "allocate emoji palettes memory " + mCurrentPagerPosition);
-        }
-        final KeyDrawParams params = new KeyDrawParams();
-        params.updateParams(mEmojiLayoutParams.getActionBarHeight(), keyVisualAttr);
-        setupAlphabetKey(mAlphabetKeyLeft, switchToAlphaLabel, params);
-        setupAlphabetKey(mAlphabetKeyRight, switchToAlphaLabel, params);
-        mEmojiPager.setAdapter(mEmojiPalettesAdapter);
-        mEmojiPager.setCurrentItem(mCurrentPagerPosition);
-    }
-
-    public void stopEmojiPalettes() {
-        if (DEBUG_PAGER) {
-            Log.d(TAG, "deallocate emoji palettes memory");
-        }
-        mEmojiPalettesAdapter.flushPendingRecentKeys();
-        mEmojiPager.setAdapter(null);
-    }
-
-    public void setKeyboardActionListener(final KeyboardActionListener listener) {
-        mKeyboardActionListener = listener;
-        mDeleteKeyOnTouchListener.setKeyboardActionListener(mKeyboardActionListener);
-    }
-
-    private void updateEmojiCategoryPageIdView() {
-        if (mEmojiCategoryPageIndicatorView == null) {
-            return;
-        }
-        mEmojiCategoryPageIndicatorView.setCategoryPageId(
-                mEmojiCategory.getCurrentCategoryPageSize(),
-                mEmojiCategory.getCurrentCategoryPageId(), 0.0f /* offset */);
-    }
-
-    private void setCurrentCategoryId(final int categoryId, final boolean force) {
-        final int oldCategoryId = mEmojiCategory.getCurrentCategoryId();
-        if (oldCategoryId == categoryId && !force) {
-            return;
-        }
-
-        if (oldCategoryId == CATEGORY_ID_RECENTS) {
-            // Needs to save pending updates for recent keys when we get out of the recents
-            // category because we don't want to move the recent emojis around while the user
-            // is in the recents category.
-            mEmojiPalettesAdapter.flushPendingRecentKeys();
-        }
-
-        mEmojiCategory.setCurrentCategoryId(categoryId);
-        final int newTabId = mEmojiCategory.getTabIdFromCategoryId(categoryId);
-        final int newCategoryPageId = mEmojiCategory.getPageIdFromCategoryId(categoryId);
-        if (force || mEmojiCategory.getCategoryIdAndPageIdFromPagePosition(
-                mEmojiPager.getCurrentItem()).first != categoryId) {
-            mEmojiPager.setCurrentItem(newCategoryPageId, false /* smoothScroll */);
-        }
-        if (force || mTabHost.getCurrentTab() != newTabId) {
-            mTabHost.setCurrentTab(newTabId);
-        }
-    }
-
-    private static class EmojiPalettesAdapter extends PagerAdapter {
-        private final EmojiPageKeyboardView.OnKeyEventListener mListener;
-        private final DynamicGridKeyboard mRecentsKeyboard;
-        private final SparseArray<EmojiPageKeyboardView> mActiveKeyboardViews =
-                CollectionUtils.newSparseArray();
-        private final EmojiCategory mEmojiCategory;
-        private int mActivePosition = 0;
-
-        public EmojiPalettesAdapter(final EmojiCategory emojiCategory,
-                final EmojiPageKeyboardView.OnKeyEventListener listener) {
-            mEmojiCategory = emojiCategory;
-            mListener = listener;
-            mRecentsKeyboard = mEmojiCategory.getKeyboard(CATEGORY_ID_RECENTS, 0);
-        }
-
-        public void flushPendingRecentKeys() {
-            mRecentsKeyboard.flushPendingRecentKeys();
-            final KeyboardView recentKeyboardView =
-                    mActiveKeyboardViews.get(mEmojiCategory.getRecentTabId());
-            if (recentKeyboardView != null) {
-                recentKeyboardView.invalidateAllKeys();
-            }
-        }
-
-        public void addRecentKey(final Key key) {
-            if (mEmojiCategory.isInRecentTab()) {
-                mRecentsKeyboard.addPendingKey(key);
-                return;
-            }
-            mRecentsKeyboard.addKeyFirst(key);
-            final KeyboardView recentKeyboardView =
-                    mActiveKeyboardViews.get(mEmojiCategory.getRecentTabId());
-            if (recentKeyboardView != null) {
-                recentKeyboardView.invalidateAllKeys();
-            }
-        }
-
-        public void onPageScrolled() {
-            // Make sure the delayed key-down event (highlight effect and haptic feedback) will be
-            // canceled.
-            final EmojiPageKeyboardView currentKeyboardView =
-                    mActiveKeyboardViews.get(mActivePosition);
-            if (currentKeyboardView != null) {
-                currentKeyboardView.releaseCurrentKey();
-            }
-        }
-
-        @Override
-        public int getCount() {
-            return mEmojiCategory.getTotalPageCountOfAllCategories();
-        }
-
-        @Override
-        public void setPrimaryItem(final ViewGroup container, final int position,
-                final Object object) {
-            if (mActivePosition == position) {
-                return;
-            }
-            final EmojiPageKeyboardView oldKeyboardView = mActiveKeyboardViews.get(mActivePosition);
-            if (oldKeyboardView != null) {
-                oldKeyboardView.releaseCurrentKey();
-                oldKeyboardView.deallocateMemory();
-            }
-            mActivePosition = position;
-        }
-
-        @Override
-        public Object instantiateItem(final ViewGroup container, final int position) {
-            if (DEBUG_PAGER) {
-                Log.d(TAG, "instantiate item: " + position);
-            }
-            final EmojiPageKeyboardView oldKeyboardView = mActiveKeyboardViews.get(position);
-            if (oldKeyboardView != null) {
-                oldKeyboardView.deallocateMemory();
-                // This may be redundant but wanted to be safer..
-                mActiveKeyboardViews.remove(position);
-            }
-            final Keyboard keyboard =
-                    mEmojiCategory.getKeyboardFromPagePosition(position);
-            final LayoutInflater inflater = LayoutInflater.from(container.getContext());
-            final EmojiPageKeyboardView keyboardView = (EmojiPageKeyboardView)inflater.inflate(
-                    R.layout.emoji_keyboard_page, container, false /* attachToRoot */);
-            keyboardView.setKeyboard(keyboard);
-            keyboardView.setOnKeyEventListener(mListener);
-            container.addView(keyboardView);
-            mActiveKeyboardViews.put(position, keyboardView);
-            return keyboardView;
-        }
-
-        @Override
-        public boolean isViewFromObject(final View view, final Object object) {
-            return view == object;
-        }
-
-        @Override
-        public void destroyItem(final ViewGroup container, final int position,
-                final Object object) {
-            if (DEBUG_PAGER) {
-                Log.d(TAG, "destroy item: " + position + ", " + object.getClass().getSimpleName());
-            }
-            final EmojiPageKeyboardView keyboardView = mActiveKeyboardViews.get(position);
-            if (keyboardView != null) {
-                keyboardView.deallocateMemory();
-                mActiveKeyboardViews.remove(position);
-            }
-            if (object instanceof View) {
-                container.removeView((View)object);
-            } else {
-                Log.w(TAG, "Warning!!! Emoji palette may be leaking. " + object);
-            }
-        }
-    }
-
-    private static class DeleteKeyOnTouchListener implements OnTouchListener {
-        private static final long MAX_REPEAT_COUNT_TIME = TimeUnit.SECONDS.toMillis(30);
-        private final int mDeleteKeyPressedBackgroundColor;
-        private final long mKeyRepeatStartTimeout;
-        private final long mKeyRepeatInterval;
-
-        public DeleteKeyOnTouchListener(Context context) {
-            final Resources res = context.getResources();
-            mDeleteKeyPressedBackgroundColor =
-                    res.getColor(R.color.emoji_key_pressed_background_color);
-            mKeyRepeatStartTimeout = res.getInteger(R.integer.config_key_repeat_start_timeout);
-            mKeyRepeatInterval = res.getInteger(R.integer.config_key_repeat_interval);
-            mTimer = new CountDownTimer(MAX_REPEAT_COUNT_TIME, mKeyRepeatInterval) {
-                @Override
-                public void onTick(long millisUntilFinished) {
-                    final long elapsed = MAX_REPEAT_COUNT_TIME - millisUntilFinished;
-                    if (elapsed < mKeyRepeatStartTimeout) {
-                        return;
-                    }
-                    onKeyRepeat();
-                }
-                @Override
-                public void onFinish() {
-                    onKeyRepeat();
-                }
-            };
-        }
-
-        /** Key-repeat state. */
-        private static final int KEY_REPEAT_STATE_INITIALIZED = 0;
-        // The key is touched but auto key-repeat is not started yet.
-        private static final int KEY_REPEAT_STATE_KEY_DOWN = 1;
-        // At least one key-repeat event has already been triggered and the key is not released.
-        private static final int KEY_REPEAT_STATE_KEY_REPEAT = 2;
-
-        private KeyboardActionListener mKeyboardActionListener =
-                KeyboardActionListener.EMPTY_LISTENER;
-
-        // TODO: Do the same things done in PointerTracker
-        private final CountDownTimer mTimer;
-        private int mState = KEY_REPEAT_STATE_INITIALIZED;
-        private int mRepeatCount = 0;
-
-        public void setKeyboardActionListener(final KeyboardActionListener listener) {
-            mKeyboardActionListener = listener;
-        }
-
-        @Override
-        public boolean onTouch(final View v, final MotionEvent event) {
-            switch (event.getActionMasked()) {
-            case MotionEvent.ACTION_DOWN:
-                onTouchDown(v);
-                return true;
-            case MotionEvent.ACTION_MOVE:
-                final float x = event.getX();
-                final float y = event.getY();
-                if (x < 0.0f || v.getWidth() < x || y < 0.0f || v.getHeight() < y) {
-                    // Stop generating key events once the finger moves away from the view area.
-                    onTouchCanceled(v);
-                }
-                return true;
-            case MotionEvent.ACTION_CANCEL:
-            case MotionEvent.ACTION_UP:
-                onTouchUp(v);
-                return true;
-            }
-            return false;
-        }
-
-        private void handleKeyDown() {
-            mKeyboardActionListener.onPressKey(
-                    Constants.CODE_DELETE, mRepeatCount, true /* isSinglePointer */);
-        }
-
-        private void handleKeyUp() {
-            mKeyboardActionListener.onCodeInput(Constants.CODE_DELETE,
-                    NOT_A_COORDINATE, NOT_A_COORDINATE, false /* isKeyRepeat */);
-            mKeyboardActionListener.onReleaseKey(
-                    Constants.CODE_DELETE, false /* withSliding */);
-            ++mRepeatCount;
-        }
-
-        private void onTouchDown(final View v) {
-            mTimer.cancel();
-            mRepeatCount = 0;
-            handleKeyDown();
-            v.setBackgroundColor(mDeleteKeyPressedBackgroundColor);
-            mState = KEY_REPEAT_STATE_KEY_DOWN;
-            mTimer.start();
-        }
-
-        private void onTouchUp(final View v) {
-            mTimer.cancel();
-            if (mState == KEY_REPEAT_STATE_KEY_DOWN) {
-                handleKeyUp();
-            }
-            v.setBackgroundColor(Color.TRANSPARENT);
-            mState = KEY_REPEAT_STATE_INITIALIZED;
-        }
-
-        private void onTouchCanceled(final View v) {
-            mTimer.cancel();
-            v.setBackgroundColor(Color.TRANSPARENT);
-            mState = KEY_REPEAT_STATE_INITIALIZED;
-        }
-
-        // Called by {@link #mTimer} in the UI thread as an auto key-repeat signal.
-        private void onKeyRepeat() {
-            switch (mState) {
-            case KEY_REPEAT_STATE_INITIALIZED:
-                // Basically this should not happen.
-                break;
-            case KEY_REPEAT_STATE_KEY_DOWN:
-                // Do not call {@link #handleKeyDown} here because it has already been called
-                // in {@link #onTouchDown}.
-                handleKeyUp();
-                mState = KEY_REPEAT_STATE_KEY_REPEAT;
-                break;
-            case KEY_REPEAT_STATE_KEY_REPEAT:
-                handleKeyDown();
-                handleKeyUp();
-                break;
-            }
-        }
-    }
-}
diff --git a/java/src/com/android/inputmethod/keyboard/Key.java b/java/src/com/android/inputmethod/keyboard/Key.java
index 816a943..4c22507 100644
--- a/java/src/com/android/inputmethod/keyboard/Key.java
+++ b/java/src/com/android/inputmethod/keyboard/Key.java
@@ -218,7 +218,7 @@
      *
      * @param keySpec the key specification.
      * @param keyAttr the Key XML attributes array.
-     * @param keyStyle the {@link KeyStyle} of this key.
+     * @param style the {@link KeyStyle} of this key.
      * @param params the keyboard building parameters.
      * @param row the row that this key belongs to. row's x-coordinate will be the right edge of
      *        this key.
@@ -857,17 +857,6 @@
         android.R.attr.state_empty
     };
 
-    // functional normal state (with properties)
-    private static final int[] KEY_STATE_FUNCTIONAL_NORMAL = {
-            android.R.attr.state_single
-    };
-
-    // functional pressed state (with properties)
-    private static final int[] KEY_STATE_FUNCTIONAL_PRESSED = {
-            android.R.attr.state_single,
-            android.R.attr.state_pressed
-    };
-
     // action normal state (with properties)
     private static final int[] KEY_STATE_ACTIVE_NORMAL = {
             android.R.attr.state_active
@@ -880,25 +869,43 @@
     };
 
     /**
-     * Returns the drawable state for the key, based on the current state and type of the key.
-     * @return the drawable state of the key.
+     * Returns the background drawable for the key, based on the current state and type of the key.
+     * @return the background drawable of the key.
      * @see android.graphics.drawable.StateListDrawable#setState(int[])
      */
-    public final int[] getCurrentDrawableState() {
-        switch (mBackgroundType) {
-        case BACKGROUND_TYPE_FUNCTIONAL:
-            return mPressed ? KEY_STATE_FUNCTIONAL_PRESSED : KEY_STATE_FUNCTIONAL_NORMAL;
-        case BACKGROUND_TYPE_ACTION:
-            return mPressed ? KEY_STATE_ACTIVE_PRESSED : KEY_STATE_ACTIVE_NORMAL;
-        case BACKGROUND_TYPE_STICKY_OFF:
-            return mPressed ? KEY_STATE_PRESSED_HIGHLIGHT_OFF : KEY_STATE_NORMAL_HIGHLIGHT_OFF;
-        case BACKGROUND_TYPE_STICKY_ON:
-            return mPressed ? KEY_STATE_PRESSED_HIGHLIGHT_ON : KEY_STATE_NORMAL_HIGHLIGHT_ON;
-        case BACKGROUND_TYPE_EMPTY:
-            return mPressed ? KEY_STATE_PRESSED : KEY_STATE_EMPTY;
-        default: /* BACKGROUND_TYPE_NORMAL */
-            return mPressed ? KEY_STATE_PRESSED : KEY_STATE_NORMAL;
+    public final Drawable selectBackgroundDrawable(final Drawable keyBackground,
+            final Drawable functionalKeyBackground, final Drawable spacebarBackground) {
+        final Drawable background;
+        if (mBackgroundType == BACKGROUND_TYPE_FUNCTIONAL) {
+            background = functionalKeyBackground;
+        } else if (getCode() == Constants.CODE_SPACE) {
+            background = spacebarBackground;
+        } else {
+            background = keyBackground;
         }
+        final int[] stateSet;
+        switch (mBackgroundType) {
+        case BACKGROUND_TYPE_ACTION:
+            stateSet = mPressed ? KEY_STATE_ACTIVE_PRESSED : KEY_STATE_ACTIVE_NORMAL;
+            break;
+        case BACKGROUND_TYPE_STICKY_OFF:
+            stateSet = mPressed ? KEY_STATE_PRESSED_HIGHLIGHT_OFF : KEY_STATE_NORMAL_HIGHLIGHT_OFF;
+            break;
+        case BACKGROUND_TYPE_STICKY_ON:
+            stateSet = mPressed ? KEY_STATE_PRESSED_HIGHLIGHT_ON : KEY_STATE_NORMAL_HIGHLIGHT_ON;
+            break;
+        case BACKGROUND_TYPE_EMPTY:
+            stateSet = mPressed ? KEY_STATE_PRESSED : KEY_STATE_EMPTY;
+            break;
+        case BACKGROUND_TYPE_FUNCTIONAL:
+            stateSet = mPressed ? KEY_STATE_PRESSED : KEY_STATE_NORMAL;
+            break;
+        default: /* BACKGROUND_TYPE_NORMAL */
+            stateSet = mPressed ? KEY_STATE_PRESSED : KEY_STATE_NORMAL;
+            break;
+        }
+        background.setState(stateSet);
+        return background;
     }
 
     public static class Spacer extends Key {
diff --git a/java/src/com/android/inputmethod/keyboard/KeyboardSwitcher.java b/java/src/com/android/inputmethod/keyboard/KeyboardSwitcher.java
index 4a46a4a..fc9faa6 100644
--- a/java/src/com/android/inputmethod/keyboard/KeyboardSwitcher.java
+++ b/java/src/com/android/inputmethod/keyboard/KeyboardSwitcher.java
@@ -28,6 +28,7 @@
 
 import com.android.inputmethod.compat.InputMethodServiceCompatUtils;
 import com.android.inputmethod.keyboard.KeyboardLayoutSet.KeyboardLayoutSetException;
+import com.android.inputmethod.keyboard.emoji.EmojiPalettesView;
 import com.android.inputmethod.keyboard.internal.KeyboardState;
 import com.android.inputmethod.keyboard.internal.KeyboardTextsSet;
 import com.android.inputmethod.latin.InputView;
@@ -253,10 +254,11 @@
     // Implements {@link KeyboardState.SwitchActions}.
     @Override
     public void setEmojiKeyboard() {
+        final Keyboard keyboard = mKeyboardView.getKeyboard();
         mMainKeyboardFrame.setVisibility(View.GONE);
         mEmojiPalettesView.startEmojiPalettes(
                 mKeyboardTextsSet.getText(KeyboardTextsSet.SWITCH_TO_ALPHA_KEY_LABEL),
-                mKeyboardView.getKeyVisualAttribute());
+                mKeyboardView.getKeyVisualAttribute(), keyboard.mIconsSet);
         mEmojiPalettesView.setVisibility(View.VISIBLE);
     }
 
diff --git a/java/src/com/android/inputmethod/keyboard/KeyboardTheme.java b/java/src/com/android/inputmethod/keyboard/KeyboardTheme.java
index 429c7dd..e0b74fa 100644
--- a/java/src/com/android/inputmethod/keyboard/KeyboardTheme.java
+++ b/java/src/com/android/inputmethod/keyboard/KeyboardTheme.java
@@ -34,7 +34,7 @@
 
     static final int THEME_ID_ICS = 0;
     static final int THEME_ID_KLP = 2;
-    static final int THEME_ID_LMP = 3;
+    static final int THEME_ID_LXX = 3;
     static final int DEFAULT_THEME_ID = THEME_ID_KLP;
 
     private static final KeyboardTheme[] KEYBOARD_THEMES = {
@@ -42,7 +42,7 @@
                 VERSION_CODES.ICE_CREAM_SANDWICH),
         new KeyboardTheme(THEME_ID_KLP, R.style.KeyboardTheme_KLP,
                 VERSION_CODES.KITKAT),
-        new KeyboardTheme(THEME_ID_LMP, R.style.KeyboardTheme_LMP,
+        new KeyboardTheme(THEME_ID_LXX, R.style.KeyboardTheme_LXX,
                 // TODO: Update this constant once the *next* version becomes available.
                 VERSION_CODES.CUR_DEVELOPMENT),
     };
@@ -88,7 +88,7 @@
             return 5;
         case THEME_ID_KLP:
             return 9;
-        case THEME_ID_LMP:
+        case THEME_ID_LXX:
             return 10;
         default: // Invalid theme
             return -1;
diff --git a/java/src/com/android/inputmethod/keyboard/KeyboardView.java b/java/src/com/android/inputmethod/keyboard/KeyboardView.java
index 4450a44..a6eac4c 100644
--- a/java/src/com/android/inputmethod/keyboard/KeyboardView.java
+++ b/java/src/com/android/inputmethod/keyboard/KeyboardView.java
@@ -47,6 +47,8 @@
  * A view that renders a virtual {@link Keyboard}.
  *
  * @attr ref R.styleable#KeyboardView_keyBackground
+ * @attr ref R.styleable#KeyboardView_functionalKeyBackground
+ * @attr ref R.styleable#KeyboardView_spacebarBackground
  * @attr ref R.styleable#KeyboardView_keyLabelHorizontalPadding
  * @attr ref R.styleable#KeyboardView_keyHintLetterPadding
  * @attr ref R.styleable#KeyboardView_keyPopupHintLetterPadding
@@ -81,6 +83,8 @@
     private final float mKeyTextShadowRadius;
     private final float mVerticalCorrection;
     private final Drawable mKeyBackground;
+    private final Drawable mFunctionalKeyBackground;
+    private final Drawable mSpacebarBackground;
     private final Rect mKeyBackgroundPadding = new Rect();
     private static final float KET_TEXT_SHADOW_RADIUS_DISABLED = -1.0f;
 
@@ -125,6 +129,14 @@
                 R.styleable.KeyboardView, defStyle, R.style.KeyboardView);
         mKeyBackground = keyboardViewAttr.getDrawable(R.styleable.KeyboardView_keyBackground);
         mKeyBackground.getPadding(mKeyBackgroundPadding);
+        final Drawable functionalKeyBackground = keyboardViewAttr.getDrawable(
+                R.styleable.KeyboardView_functionalKeyBackground);
+        mFunctionalKeyBackground = (functionalKeyBackground != null) ? functionalKeyBackground
+                : mKeyBackground;
+        final Drawable spacebarBackground = keyboardViewAttr.getDrawable(
+                R.styleable.KeyboardView_spacebarBackground);
+        mSpacebarBackground = (spacebarBackground != null) ? spacebarBackground
+                : mKeyBackground;
         mKeyLabelHorizontalPadding = keyboardViewAttr.getDimensionPixelOffset(
                 R.styleable.KeyboardView_keyLabelHorizontalPadding, 0);
         mKeyHintLetterPadding = keyboardViewAttr.getDimension(
@@ -324,7 +336,9 @@
         params.mAnimAlpha = Constants.Color.ALPHA_OPAQUE;
 
         if (!key.isSpacer()) {
-            onDrawKeyBackground(key, canvas, mKeyBackground);
+            final Drawable background = key.selectBackgroundDrawable(
+                    mKeyBackground, mFunctionalKeyBackground, mSpacebarBackground);
+            onDrawKeyBackground(key, canvas, background);
         }
         onDrawKeyTopVisuals(key, canvas, paint, params);
 
@@ -339,8 +353,6 @@
         final int bgHeight = key.getHeight() + padding.top + padding.bottom;
         final int bgX = -padding.left;
         final int bgY = -padding.top;
-        final int[] drawableState = key.getCurrentDrawableState();
-        background.setState(drawableState);
         final Rect bounds = background.getBounds();
         if (bgWidth != bounds.right || bgHeight != bounds.bottom) {
             background.setBounds(0, 0, bgWidth, bgHeight);
diff --git a/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java b/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java
index 1a8e4b7..4a09768 100644
--- a/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java
+++ b/java/src/com/android/inputmethod/keyboard/MainKeyboardView.java
@@ -76,7 +76,6 @@
  * @attr ref R.styleable#MainKeyboardView_languageOnSpacebarTextColor
  * @attr ref R.styleable#MainKeyboardView_languageOnSpacebarTextShadowRadius
  * @attr ref R.styleable#MainKeyboardView_languageOnSpacebarTextShadowColor
- * @attr ref R.styleable#MainKeyboardView_spacebarBackground
  * @attr ref R.styleable#MainKeyboardView_languageOnSpacebarFinalAlpha
  * @attr ref R.styleable#MainKeyboardView_languageOnSpacebarFadeoutAnimator
  * @attr ref R.styleable#MainKeyboardView_altCodeKeyWhileTypingFadeoutAnimator
@@ -120,7 +119,6 @@
     /* Space key and its icon and background. */
     private Key mSpaceKey;
     private Drawable mSpacebarIcon;
-    private final Drawable mSpacebarBackground;
     // Stuff to draw language name on spacebar.
     private final int mLanguageOnSpacebarFinalAlpha;
     private ObjectAnimator mLanguageOnSpacebarFadeoutAnimator;
@@ -154,7 +152,6 @@
     private final SlidingKeyInputDrawingPreview mSlidingKeyInputDrawingPreview;
 
     // Key preview
-    private static final boolean FADE_OUT_KEY_TOP_LETTER_WHEN_KEY_IS_PRESSED = false;
     private final KeyPreviewDrawParams mKeyPreviewDrawParams;
     private final KeyPreviewChoreographer mKeyPreviewChoreographer;
 
@@ -224,8 +221,6 @@
                 R.styleable.MainKeyboardView_backgroundDimAlpha, 0);
         mBackgroundDimAlphaPaint.setColor(Color.BLACK);
         mBackgroundDimAlphaPaint.setAlpha(backgroundDimAlpha);
-        mSpacebarBackground = mainKeyboardViewAttr.getDrawable(
-                R.styleable.MainKeyboardView_spacebarBackground);
         mAutoCorrectionSpacebarLedEnabled = mainKeyboardViewAttr.getBoolean(
                 R.styleable.MainKeyboardView_autoCorrectionSpacebarLedEnabled, false);
         mAutoCorrectionSpacebarLedIcon = mainKeyboardViewAttr.getDrawable(
@@ -557,6 +552,7 @@
     }
 
     // Note that this method is called from a non-UI thread.
+    @SuppressWarnings("static-method")
     public void setMainDictionaryAvailability(final boolean mainDictionaryAvailable) {
         PointerTracker.setMainDictionaryAvailability(mainDictionaryAvailable);
     }
@@ -864,30 +860,12 @@
         }
     }
 
-    // Draw key background.
-    @Override
-    protected void onDrawKeyBackground(final Key key, final Canvas canvas,
-            final Drawable background) {
-        if (key.getCode() == Constants.CODE_SPACE) {
-            super.onDrawKeyBackground(key, canvas, mSpacebarBackground);
-            return;
-        }
-        super.onDrawKeyBackground(key, canvas, background);
-    }
-
     @Override
     protected void onDrawKeyTopVisuals(final Key key, final Canvas canvas, final Paint paint,
             final KeyDrawParams params) {
         if (key.altCodeWhileTyping() && key.isEnabled()) {
             params.mAnimAlpha = mAltCodeKeyWhileTypingAnimAlpha;
         }
-        // Don't draw key top letter when key preview is showing.
-        if (FADE_OUT_KEY_TOP_LETTER_WHEN_KEY_IS_PRESSED
-                && mKeyPreviewChoreographer.isShowingKeyPreview(key)) {
-            // TODO: Fade out animation for the key top letter, and fade in animation for the key
-            // background color when the user presses the key.
-            return;
-        }
         final int code = key.getCode();
         if (code == Constants.CODE_SPACE) {
             drawSpacebar(key, canvas, paint);
diff --git a/java/src/com/android/inputmethod/keyboard/internal/DynamicGridKeyboard.java b/java/src/com/android/inputmethod/keyboard/emoji/DynamicGridKeyboard.java
similarity index 97%
rename from java/src/com/android/inputmethod/keyboard/internal/DynamicGridKeyboard.java
rename to java/src/com/android/inputmethod/keyboard/emoji/DynamicGridKeyboard.java
index 67a2227..c7a9025 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/DynamicGridKeyboard.java
+++ b/java/src/com/android/inputmethod/keyboard/emoji/DynamicGridKeyboard.java
@@ -14,13 +14,12 @@
  * limitations under the License.
  */
 
-package com.android.inputmethod.keyboard.internal;
+package com.android.inputmethod.keyboard.emoji;
 
 import android.content.SharedPreferences;
 import android.text.TextUtils;
 import android.util.Log;
 
-import com.android.inputmethod.keyboard.EmojiPalettesView;
 import com.android.inputmethod.keyboard.Key;
 import com.android.inputmethod.keyboard.Keyboard;
 import com.android.inputmethod.latin.settings.Settings;
@@ -36,7 +35,7 @@
 /**
  * This is a Keyboard class where you can add keys dynamically shown in a grid layout
  */
-public class DynamicGridKeyboard extends Keyboard {
+final class DynamicGridKeyboard extends Keyboard {
     private static final String TAG = DynamicGridKeyboard.class.getSimpleName();
     private static final int TEMPLATE_KEY_CODE_0 = 0x30;
     private static final int TEMPLATE_KEY_CODE_1 = 0x31;
@@ -62,7 +61,7 @@
         mVerticalStep = key0.getHeight() + mVerticalGap;
         mColumnsNum = mBaseWidth / mHorizontalStep;
         mMaxKeyCount = maxKeyCount;
-        mIsRecents = categoryId == EmojiPalettesView.CATEGORY_ID_RECENTS;
+        mIsRecents = categoryId == EmojiCategory.ID_RECENTS;
         mPrefs = prefs;
     }
 
diff --git a/java/src/com/android/inputmethod/keyboard/emoji/EmojiCategory.java b/java/src/com/android/inputmethod/keyboard/emoji/EmojiCategory.java
new file mode 100644
index 0000000..dd0e3e8
--- /dev/null
+++ b/java/src/com/android/inputmethod/keyboard/emoji/EmojiCategory.java
@@ -0,0 +1,358 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.inputmethod.keyboard.emoji;
+
+import android.content.SharedPreferences;
+import android.content.res.Resources;
+import android.graphics.Rect;
+import android.os.Build;
+import android.util.Log;
+import android.util.Pair;
+
+import com.android.inputmethod.keyboard.Key;
+import com.android.inputmethod.keyboard.Keyboard;
+import com.android.inputmethod.keyboard.KeyboardId;
+import com.android.inputmethod.keyboard.KeyboardLayoutSet;
+import com.android.inputmethod.latin.Constants;
+import com.android.inputmethod.latin.R;
+import com.android.inputmethod.latin.settings.Settings;
+import com.android.inputmethod.latin.utils.CollectionUtils;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.List;
+import java.util.concurrent.ConcurrentHashMap;
+
+final class EmojiCategory {
+    private final String TAG = EmojiCategory.class.getSimpleName();
+
+    private static final int ID_UNSPECIFIED = -1;
+    public static final int ID_RECENTS = 0;
+    private static final int ID_PEOPLE = 1;
+    private static final int ID_OBJECTS = 2;
+    private static final int ID_NATURE = 3;
+    private static final int ID_PLACES = 4;
+    private static final int ID_SYMBOLS = 5;
+    private static final int ID_EMOTICONS = 6;
+
+    public final class CategoryProperties {
+        public final int mCategoryId;
+        public final int mPageCount;
+        public CategoryProperties(final int categoryId, final int pageCount) {
+            mCategoryId = categoryId;
+            mPageCount = pageCount;
+        }
+    }
+
+    private static final String[] sCategoryName = {
+            "recents",
+            "people",
+            "objects",
+            "nature",
+            "places",
+            "symbols",
+            "emoticons" };
+
+    private static final int[] sCategoryIcon = {
+            R.drawable.ic_emoji_recent_light,
+            R.drawable.ic_emoji_people_light,
+            R.drawable.ic_emoji_objects_light,
+            R.drawable.ic_emoji_nature_light,
+            R.drawable.ic_emoji_places_light,
+            R.drawable.ic_emoji_symbols_light,
+            0 };
+
+    private static final String[] sCategoryLabel =
+            { null, null, null, null, null, null, ":-)" };
+
+    private static final int[] sAccessibilityDescriptionResourceIdsForCategories = {
+            R.string.spoken_descrption_emoji_category_recents,
+            R.string.spoken_descrption_emoji_category_people,
+            R.string.spoken_descrption_emoji_category_objects,
+            R.string.spoken_descrption_emoji_category_nature,
+            R.string.spoken_descrption_emoji_category_places,
+            R.string.spoken_descrption_emoji_category_symbols,
+            R.string.spoken_descrption_emoji_category_emoticons };
+
+    private static final int[] sCategoryElementId = {
+            KeyboardId.ELEMENT_EMOJI_RECENTS,
+            KeyboardId.ELEMENT_EMOJI_CATEGORY1,
+            KeyboardId.ELEMENT_EMOJI_CATEGORY2,
+            KeyboardId.ELEMENT_EMOJI_CATEGORY3,
+            KeyboardId.ELEMENT_EMOJI_CATEGORY4,
+            KeyboardId.ELEMENT_EMOJI_CATEGORY5,
+            KeyboardId.ELEMENT_EMOJI_CATEGORY6 };
+
+    private final SharedPreferences mPrefs;
+    private final Resources mRes;
+    private final int mMaxPageKeyCount;
+    private final KeyboardLayoutSet mLayoutSet;
+    private final HashMap<String, Integer> mCategoryNameToIdMap = CollectionUtils.newHashMap();
+    private final ArrayList<CategoryProperties> mShownCategories =
+            CollectionUtils.newArrayList();
+    private final ConcurrentHashMap<Long, DynamicGridKeyboard>
+            mCategoryKeyboardMap = new ConcurrentHashMap<Long, DynamicGridKeyboard>();
+
+    private int mCurrentCategoryId = EmojiCategory.ID_UNSPECIFIED;
+    private int mCurrentCategoryPageId = 0;
+
+    public EmojiCategory(final SharedPreferences prefs, final Resources res,
+            final KeyboardLayoutSet layoutSet) {
+        mPrefs = prefs;
+        mRes = res;
+        mMaxPageKeyCount = res.getInteger(R.integer.config_emoji_keyboard_max_page_key_count);
+        mLayoutSet = layoutSet;
+        for (int i = 0; i < sCategoryName.length; ++i) {
+            mCategoryNameToIdMap.put(sCategoryName[i], i);
+        }
+        addShownCategoryId(EmojiCategory.ID_RECENTS);
+        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.JELLY_BEAN_MR2
+                || android.os.Build.VERSION.CODENAME.equalsIgnoreCase("KeyLimePie")
+                || android.os.Build.VERSION.CODENAME.equalsIgnoreCase("KitKat")) {
+            addShownCategoryId(EmojiCategory.ID_PEOPLE);
+            addShownCategoryId(EmojiCategory.ID_OBJECTS);
+            addShownCategoryId(EmojiCategory.ID_NATURE);
+            addShownCategoryId(EmojiCategory.ID_PLACES);
+            mCurrentCategoryId =
+                    Settings.readLastShownEmojiCategoryId(mPrefs, EmojiCategory.ID_PEOPLE);
+        } else {
+            mCurrentCategoryId =
+                    Settings.readLastShownEmojiCategoryId(mPrefs, EmojiCategory.ID_SYMBOLS);
+        }
+        addShownCategoryId(EmojiCategory.ID_SYMBOLS);
+        addShownCategoryId(EmojiCategory.ID_EMOTICONS);
+        getKeyboard(EmojiCategory.ID_RECENTS, 0 /* cagetoryPageId */)
+                .loadRecentKeys(mCategoryKeyboardMap.values());
+    }
+
+    private void addShownCategoryId(final int categoryId) {
+        // Load a keyboard of categoryId
+        getKeyboard(categoryId, 0 /* cagetoryPageId */);
+        final CategoryProperties properties =
+                new CategoryProperties(categoryId, getCategoryPageCount(categoryId));
+        mShownCategories.add(properties);
+    }
+
+    public String getCategoryName(final int categoryId, final int categoryPageId) {
+        return sCategoryName[categoryId] + "-" + categoryPageId;
+    }
+
+    public int getCategoryId(final String name) {
+        final String[] strings = name.split("-");
+        return mCategoryNameToIdMap.get(strings[0]);
+    }
+
+    public int getCategoryIcon(final int categoryId) {
+        return sCategoryIcon[categoryId];
+    }
+
+    public String getCategoryLabel(final int categoryId) {
+        return sCategoryLabel[categoryId];
+    }
+
+    public String getAccessibilityDescription(final int categoryId) {
+        return mRes.getString(sAccessibilityDescriptionResourceIdsForCategories[categoryId]);
+    }
+
+    public ArrayList<CategoryProperties> getShownCategories() {
+        return mShownCategories;
+    }
+
+    public int getCurrentCategoryId() {
+        return mCurrentCategoryId;
+    }
+
+    public int getCurrentCategoryPageSize() {
+        return getCategoryPageSize(mCurrentCategoryId);
+    }
+
+    public int getCategoryPageSize(final int categoryId) {
+        for (final CategoryProperties prop : mShownCategories) {
+            if (prop.mCategoryId == categoryId) {
+                return prop.mPageCount;
+            }
+        }
+        Log.w(TAG, "Invalid category id: " + categoryId);
+        // Should not reach here.
+        return 0;
+    }
+
+    public void setCurrentCategoryId(final int categoryId) {
+        mCurrentCategoryId = categoryId;
+        Settings.writeLastShownEmojiCategoryId(mPrefs, categoryId);
+    }
+
+    public void setCurrentCategoryPageId(final int id) {
+        mCurrentCategoryPageId = id;
+    }
+
+    public int getCurrentCategoryPageId() {
+        return mCurrentCategoryPageId;
+    }
+
+    public void saveLastTypedCategoryPage() {
+        Settings.writeLastTypedEmojiCategoryPageId(
+                mPrefs, mCurrentCategoryId, mCurrentCategoryPageId);
+    }
+
+    public boolean isInRecentTab() {
+        return mCurrentCategoryId == EmojiCategory.ID_RECENTS;
+    }
+
+    public int getTabIdFromCategoryId(final int categoryId) {
+        for (int i = 0; i < mShownCategories.size(); ++i) {
+            if (mShownCategories.get(i).mCategoryId == categoryId) {
+                return i;
+            }
+        }
+        Log.w(TAG, "categoryId not found: " + categoryId);
+        return 0;
+    }
+
+    // Returns the view pager's page position for the categoryId
+    public int getPageIdFromCategoryId(final int categoryId) {
+        final int lastSavedCategoryPageId =
+                Settings.readLastTypedEmojiCategoryPageId(mPrefs, categoryId);
+        int sum = 0;
+        for (int i = 0; i < mShownCategories.size(); ++i) {
+            final CategoryProperties props = mShownCategories.get(i);
+            if (props.mCategoryId == categoryId) {
+                return sum + lastSavedCategoryPageId;
+            }
+            sum += props.mPageCount;
+        }
+        Log.w(TAG, "categoryId not found: " + categoryId);
+        return 0;
+    }
+
+    public int getRecentTabId() {
+        return getTabIdFromCategoryId(EmojiCategory.ID_RECENTS);
+    }
+
+    private int getCategoryPageCount(final int categoryId) {
+        final Keyboard keyboard = mLayoutSet.getKeyboard(sCategoryElementId[categoryId]);
+        return (keyboard.getSortedKeys().size() - 1) / mMaxPageKeyCount + 1;
+    }
+
+    // Returns a pair of the category id and the category page id from the view pager's page
+    // position. The category page id is numbered in each category. And the view page position
+    // is the position of the current shown page in the view pager which contains all pages of
+    // all categories.
+    public Pair<Integer, Integer> getCategoryIdAndPageIdFromPagePosition(final int position) {
+        int sum = 0;
+        for (final CategoryProperties properties : mShownCategories) {
+            final int temp = sum;
+            sum += properties.mPageCount;
+            if (sum > position) {
+                return new Pair<Integer, Integer>(properties.mCategoryId, position - temp);
+            }
+        }
+        return null;
+    }
+
+    // Returns a keyboard from the view pager's page position.
+    public DynamicGridKeyboard getKeyboardFromPagePosition(final int position) {
+        final Pair<Integer, Integer> categoryAndId =
+                getCategoryIdAndPageIdFromPagePosition(position);
+        if (categoryAndId != null) {
+            return getKeyboard(categoryAndId.first, categoryAndId.second);
+        }
+        return null;
+    }
+
+    private static final Long getCategoryKeyboardMapKey(final int categoryId, final int id) {
+        return (((long) categoryId) << Constants.MAX_INT_BIT_COUNT) | id;
+    }
+
+    public DynamicGridKeyboard getKeyboard(final int categoryId, final int id) {
+        synchronized (mCategoryKeyboardMap) {
+            final Long categotyKeyboardMapKey = getCategoryKeyboardMapKey(categoryId, id);
+            if (mCategoryKeyboardMap.containsKey(categotyKeyboardMapKey)) {
+                return mCategoryKeyboardMap.get(categotyKeyboardMapKey);
+            }
+
+            if (categoryId == EmojiCategory.ID_RECENTS) {
+                final DynamicGridKeyboard kbd = new DynamicGridKeyboard(mPrefs,
+                        mLayoutSet.getKeyboard(KeyboardId.ELEMENT_EMOJI_RECENTS),
+                        mMaxPageKeyCount, categoryId);
+                mCategoryKeyboardMap.put(categotyKeyboardMapKey, kbd);
+                return kbd;
+            }
+
+            final Keyboard keyboard = mLayoutSet.getKeyboard(sCategoryElementId[categoryId]);
+            final Key[][] sortedKeys = sortKeysIntoPages(
+                    keyboard.getSortedKeys(), mMaxPageKeyCount);
+            for (int pageId = 0; pageId < sortedKeys.length; ++pageId) {
+                final DynamicGridKeyboard tempKeyboard = new DynamicGridKeyboard(mPrefs,
+                        mLayoutSet.getKeyboard(KeyboardId.ELEMENT_EMOJI_RECENTS),
+                        mMaxPageKeyCount, categoryId);
+                for (final Key emojiKey : sortedKeys[pageId]) {
+                    if (emojiKey == null) {
+                        break;
+                    }
+                    tempKeyboard.addKeyLast(emojiKey);
+                }
+                mCategoryKeyboardMap.put(
+                        getCategoryKeyboardMapKey(categoryId, pageId), tempKeyboard);
+            }
+            return mCategoryKeyboardMap.get(categotyKeyboardMapKey);
+        }
+    }
+
+    public int getTotalPageCountOfAllCategories() {
+        int sum = 0;
+        for (CategoryProperties properties : mShownCategories) {
+            sum += properties.mPageCount;
+        }
+        return sum;
+    }
+
+    private static Comparator<Key> EMOJI_KEY_COMPARATOR = new Comparator<Key>() {
+        @Override
+        public int compare(final Key lhs, final Key rhs) {
+            final Rect lHitBox = lhs.getHitBox();
+            final Rect rHitBox = rhs.getHitBox();
+            if (lHitBox.top < rHitBox.top) {
+                return -1;
+            } else if (lHitBox.top > rHitBox.top) {
+                return 1;
+            }
+            if (lHitBox.left < rHitBox.left) {
+                return -1;
+            } else if (lHitBox.left > rHitBox.left) {
+                return 1;
+            }
+            if (lhs.getCode() == rhs.getCode()) {
+                return 0;
+            }
+            return lhs.getCode() < rhs.getCode() ? -1 : 1;
+        }
+    };
+
+    private static Key[][] sortKeysIntoPages(final List<Key> inKeys, final int maxPageCount) {
+        final ArrayList<Key> keys = CollectionUtils.newArrayList(inKeys);
+        Collections.sort(keys, EMOJI_KEY_COMPARATOR);
+        final int pageCount = (keys.size() - 1) / maxPageCount + 1;
+        final Key[][] retval = new Key[pageCount][maxPageCount];
+        for (int i = 0; i < keys.size(); ++i) {
+            retval[i / maxPageCount][i % maxPageCount] = keys.get(i);
+        }
+        return retval;
+    }
+}
diff --git a/java/src/com/android/inputmethod/keyboard/EmojiCategoryPageIndicatorView.java b/java/src/com/android/inputmethod/keyboard/emoji/EmojiCategoryPageIndicatorView.java
similarity index 92%
rename from java/src/com/android/inputmethod/keyboard/EmojiCategoryPageIndicatorView.java
rename to java/src/com/android/inputmethod/keyboard/emoji/EmojiCategoryPageIndicatorView.java
index d56a3cf..74cfd9b 100644
--- a/java/src/com/android/inputmethod/keyboard/EmojiCategoryPageIndicatorView.java
+++ b/java/src/com/android/inputmethod/keyboard/emoji/EmojiCategoryPageIndicatorView.java
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.android.inputmethod.keyboard;
+package com.android.inputmethod.keyboard.emoji;
 
 import com.android.inputmethod.latin.R;
 
@@ -24,8 +24,8 @@
 import android.util.AttributeSet;
 import android.widget.LinearLayout;
 
-public class EmojiCategoryPageIndicatorView extends LinearLayout {
-    private static final float BOTTOM_MARGIN_RATIO = 0.66f;
+public final class EmojiCategoryPageIndicatorView extends LinearLayout {
+    private static final float BOTTOM_MARGIN_RATIO = 1.0f;
     private final Paint mPaint = new Paint();
     private int mCategoryPageSize = 0;
     private int mCurrentCategoryPageId = 0;
diff --git a/java/src/com/android/inputmethod/keyboard/internal/EmojiLayoutParams.java b/java/src/com/android/inputmethod/keyboard/emoji/EmojiLayoutParams.java
similarity index 97%
rename from java/src/com/android/inputmethod/keyboard/internal/EmojiLayoutParams.java
rename to java/src/com/android/inputmethod/keyboard/emoji/EmojiLayoutParams.java
index d57ea5a..77c183a 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/EmojiLayoutParams.java
+++ b/java/src/com/android/inputmethod/keyboard/emoji/EmojiLayoutParams.java
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.android.inputmethod.keyboard.internal;
+package com.android.inputmethod.keyboard.emoji;
 
 import com.android.inputmethod.latin.R;
 import com.android.inputmethod.latin.utils.ResourceUtils;
@@ -24,7 +24,7 @@
 import android.widget.ImageView;
 import android.widget.LinearLayout;
 
-public class EmojiLayoutParams {
+final class EmojiLayoutParams {
     private static final int DEFAULT_KEYBOARD_ROWS = 4;
 
     public final int mEmojiPagerHeight;
diff --git a/java/src/com/android/inputmethod/keyboard/internal/EmojiPageKeyboardView.java b/java/src/com/android/inputmethod/keyboard/emoji/EmojiPageKeyboardView.java
similarity index 95%
rename from java/src/com/android/inputmethod/keyboard/internal/EmojiPageKeyboardView.java
rename to java/src/com/android/inputmethod/keyboard/emoji/EmojiPageKeyboardView.java
index e175a05..d14ffee 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/EmojiPageKeyboardView.java
+++ b/java/src/com/android/inputmethod/keyboard/emoji/EmojiPageKeyboardView.java
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package com.android.inputmethod.keyboard.internal;
+package com.android.inputmethod.keyboard.emoji;
 
 import android.content.Context;
 import android.os.Handler;
@@ -26,15 +26,14 @@
 import com.android.inputmethod.keyboard.KeyDetector;
 import com.android.inputmethod.keyboard.Keyboard;
 import com.android.inputmethod.keyboard.KeyboardView;
-import com.android.inputmethod.keyboard.PointerTracker;
 import com.android.inputmethod.latin.R;
 
 /**
  * This is an extended {@link KeyboardView} class that hosts an emoji page keyboard.
- * Multi-touch unsupported. No {@link PointerTracker}s. No gesture support.
+ * Multi-touch unsupported. No gesture support.
  */
 // TODO: Implement key popup preview.
-public final class EmojiPageKeyboardView extends KeyboardView implements
+final class EmojiPageKeyboardView extends KeyboardView implements
         GestureDetector.OnGestureListener {
     private static final long KEY_PRESS_DELAY_TIME = 250;  // msec
     private static final long KEY_RELEASE_DELAY_TIME = 30;  // msec
diff --git a/java/src/com/android/inputmethod/keyboard/emoji/EmojiPalettesAdapter.java b/java/src/com/android/inputmethod/keyboard/emoji/EmojiPalettesAdapter.java
new file mode 100644
index 0000000..52a4dde
--- /dev/null
+++ b/java/src/com/android/inputmethod/keyboard/emoji/EmojiPalettesAdapter.java
@@ -0,0 +1,146 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.inputmethod.keyboard.emoji;
+
+import android.support.v4.view.PagerAdapter;
+import android.util.Log;
+import android.util.SparseArray;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+
+import com.android.inputmethod.keyboard.Key;
+import com.android.inputmethod.keyboard.Keyboard;
+import com.android.inputmethod.keyboard.KeyboardView;
+import com.android.inputmethod.latin.R;
+import com.android.inputmethod.latin.utils.CollectionUtils;
+
+final class EmojiPalettesAdapter extends PagerAdapter {
+    private static final String TAG = EmojiPalettesAdapter.class.getSimpleName();
+    private static final boolean DEBUG_PAGER = false;
+
+    private final EmojiPageKeyboardView.OnKeyEventListener mListener;
+    private final DynamicGridKeyboard mRecentsKeyboard;
+    private final SparseArray<EmojiPageKeyboardView> mActiveKeyboardViews =
+            CollectionUtils.newSparseArray();
+    private final EmojiCategory mEmojiCategory;
+    private int mActivePosition = 0;
+
+    public EmojiPalettesAdapter(final EmojiCategory emojiCategory,
+            final EmojiPageKeyboardView.OnKeyEventListener listener) {
+        mEmojiCategory = emojiCategory;
+        mListener = listener;
+        mRecentsKeyboard = mEmojiCategory.getKeyboard(EmojiCategory.ID_RECENTS, 0);
+    }
+
+    public void flushPendingRecentKeys() {
+        mRecentsKeyboard.flushPendingRecentKeys();
+        final KeyboardView recentKeyboardView =
+                mActiveKeyboardViews.get(mEmojiCategory.getRecentTabId());
+        if (recentKeyboardView != null) {
+            recentKeyboardView.invalidateAllKeys();
+        }
+    }
+
+    public void addRecentKey(final Key key) {
+        if (mEmojiCategory.isInRecentTab()) {
+            mRecentsKeyboard.addPendingKey(key);
+            return;
+        }
+        mRecentsKeyboard.addKeyFirst(key);
+        final KeyboardView recentKeyboardView =
+                mActiveKeyboardViews.get(mEmojiCategory.getRecentTabId());
+        if (recentKeyboardView != null) {
+            recentKeyboardView.invalidateAllKeys();
+        }
+    }
+
+    public void onPageScrolled() {
+        // Make sure the delayed key-down event (highlight effect and haptic feedback) will be
+        // canceled.
+        final EmojiPageKeyboardView currentKeyboardView =
+                mActiveKeyboardViews.get(mActivePosition);
+        if (currentKeyboardView != null) {
+            currentKeyboardView.releaseCurrentKey();
+        }
+    }
+
+    @Override
+    public int getCount() {
+        return mEmojiCategory.getTotalPageCountOfAllCategories();
+    }
+
+    @Override
+    public void setPrimaryItem(final ViewGroup container, final int position,
+            final Object object) {
+        if (mActivePosition == position) {
+            return;
+        }
+        final EmojiPageKeyboardView oldKeyboardView = mActiveKeyboardViews.get(mActivePosition);
+        if (oldKeyboardView != null) {
+            oldKeyboardView.releaseCurrentKey();
+            oldKeyboardView.deallocateMemory();
+        }
+        mActivePosition = position;
+    }
+
+    @Override
+    public Object instantiateItem(final ViewGroup container, final int position) {
+        if (DEBUG_PAGER) {
+            Log.d(TAG, "instantiate item: " + position);
+        }
+        final EmojiPageKeyboardView oldKeyboardView = mActiveKeyboardViews.get(position);
+        if (oldKeyboardView != null) {
+            oldKeyboardView.deallocateMemory();
+            // This may be redundant but wanted to be safer..
+            mActiveKeyboardViews.remove(position);
+        }
+        final Keyboard keyboard =
+                mEmojiCategory.getKeyboardFromPagePosition(position);
+        final LayoutInflater inflater = LayoutInflater.from(container.getContext());
+        final EmojiPageKeyboardView keyboardView = (EmojiPageKeyboardView)inflater.inflate(
+                R.layout.emoji_keyboard_page, container, false /* attachToRoot */);
+        keyboardView.setKeyboard(keyboard);
+        keyboardView.setOnKeyEventListener(mListener);
+        container.addView(keyboardView);
+        mActiveKeyboardViews.put(position, keyboardView);
+        return keyboardView;
+    }
+
+    @Override
+    public boolean isViewFromObject(final View view, final Object object) {
+        return view == object;
+    }
+
+    @Override
+    public void destroyItem(final ViewGroup container, final int position,
+            final Object object) {
+        if (DEBUG_PAGER) {
+            Log.d(TAG, "destroy item: " + position + ", " + object.getClass().getSimpleName());
+        }
+        final EmojiPageKeyboardView keyboardView = mActiveKeyboardViews.get(position);
+        if (keyboardView != null) {
+            keyboardView.deallocateMemory();
+            mActiveKeyboardViews.remove(position);
+        }
+        if (object instanceof View) {
+            container.removeView((View)object);
+        } else {
+            Log.w(TAG, "Warning!!! Emoji palette may be leaking. " + object);
+        }
+    }
+}
diff --git a/java/src/com/android/inputmethod/keyboard/emoji/EmojiPalettesView.java b/java/src/com/android/inputmethod/keyboard/emoji/EmojiPalettesView.java
new file mode 100644
index 0000000..3813c57
--- /dev/null
+++ b/java/src/com/android/inputmethod/keyboard/emoji/EmojiPalettesView.java
@@ -0,0 +1,542 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.inputmethod.keyboard.emoji;
+
+import static com.android.inputmethod.latin.Constants.NOT_A_COORDINATE;
+
+import android.content.Context;
+import android.content.res.ColorStateList;
+import android.content.res.Resources;
+import android.content.res.TypedArray;
+import android.graphics.Color;
+import android.graphics.Typeface;
+import android.os.CountDownTimer;
+import android.preference.PreferenceManager;
+import android.support.v4.view.ViewPager;
+import android.util.AttributeSet;
+import android.util.Pair;
+import android.util.TypedValue;
+import android.view.LayoutInflater;
+import android.view.MotionEvent;
+import android.view.View;
+import android.widget.ImageButton;
+import android.widget.ImageView;
+import android.widget.LinearLayout;
+import android.widget.TabHost;
+import android.widget.TabHost.OnTabChangeListener;
+import android.widget.TextView;
+
+import com.android.inputmethod.keyboard.Key;
+import com.android.inputmethod.keyboard.KeyboardActionListener;
+import com.android.inputmethod.keyboard.KeyboardLayoutSet;
+import com.android.inputmethod.keyboard.KeyboardView;
+import com.android.inputmethod.keyboard.internal.KeyDrawParams;
+import com.android.inputmethod.keyboard.internal.KeyVisualAttributes;
+import com.android.inputmethod.keyboard.internal.KeyboardIconsSet;
+import com.android.inputmethod.latin.Constants;
+import com.android.inputmethod.latin.R;
+import com.android.inputmethod.latin.SubtypeSwitcher;
+import com.android.inputmethod.latin.utils.ResourceUtils;
+
+import java.util.concurrent.TimeUnit;
+
+/**
+ * View class to implement Emoji palettes.
+ * The Emoji keyboard consists of group of views {@link R.layout#emoji_palettes_view}.
+ * <ol>
+ * <li> Emoji category tabs.
+ * <li> Delete button.
+ * <li> Emoji keyboard pages that can be scrolled by swiping horizontally or by selecting a tab.
+ * <li> Back to main keyboard button and enter button.
+ * </ol>
+ * Because of the above reasons, this class doesn't extend {@link KeyboardView}.
+ */
+public final class EmojiPalettesView extends LinearLayout implements OnTabChangeListener,
+        ViewPager.OnPageChangeListener, View.OnClickListener, View.OnTouchListener,
+        EmojiPageKeyboardView.OnKeyEventListener {
+    private final int mFunctionalKeyBackgroundId;
+    private final int mSpacebarBackgroundId;
+    private final ColorStateList mTabLabelColor;
+    private final DeleteKeyOnTouchListener mDeleteKeyOnTouchListener;
+    private EmojiPalettesAdapter mEmojiPalettesAdapter;
+    private final EmojiLayoutParams mEmojiLayoutParams;
+
+    private ImageButton mDeleteKey;
+    private TextView mAlphabetKeyLeft;
+    private TextView mAlphabetKeyRight;
+    private ImageButton mSpacebar;
+    private TabHost mTabHost;
+    private ViewPager mEmojiPager;
+    private int mCurrentPagerPosition = 0;
+    private EmojiCategoryPageIndicatorView mEmojiCategoryPageIndicatorView;
+
+    private KeyboardActionListener mKeyboardActionListener = KeyboardActionListener.EMPTY_LISTENER;
+
+    private final EmojiCategory mEmojiCategory;
+
+    public EmojiPalettesView(final Context context, final AttributeSet attrs) {
+        this(context, attrs, R.attr.emojiPalettesViewStyle);
+    }
+
+    public EmojiPalettesView(final Context context, final AttributeSet attrs, final int defStyle) {
+        super(context, attrs, defStyle);
+        final TypedArray keyboardViewAttr = context.obtainStyledAttributes(attrs,
+                R.styleable.KeyboardView, defStyle, R.style.KeyboardView);
+        final int keyBackgroundId = keyboardViewAttr.getResourceId(
+                R.styleable.KeyboardView_keyBackground, 0);
+        mFunctionalKeyBackgroundId = keyboardViewAttr.getResourceId(
+                R.styleable.KeyboardView_functionalKeyBackground, keyBackgroundId);
+        mSpacebarBackgroundId = keyboardViewAttr.getResourceId(
+                R.styleable.KeyboardView_spacebarBackground, keyBackgroundId);
+        keyboardViewAttr.recycle();
+        final TypedArray emojiPalettesViewAttr = context.obtainStyledAttributes(attrs,
+                R.styleable.EmojiPalettesView, defStyle, R.style.EmojiPalettesView);
+        mTabLabelColor = emojiPalettesViewAttr.getColorStateList(
+                R.styleable.EmojiPalettesView_emojiTabLabelColor);
+        emojiPalettesViewAttr.recycle();
+        final KeyboardLayoutSet.Builder builder = new KeyboardLayoutSet.Builder(
+                context, null /* editorInfo */);
+        final Resources res = context.getResources();
+        mEmojiLayoutParams = new EmojiLayoutParams(res);
+        builder.setSubtype(SubtypeSwitcher.getInstance().getEmojiSubtype());
+        builder.setKeyboardGeometry(ResourceUtils.getDefaultKeyboardWidth(res),
+                mEmojiLayoutParams.mEmojiKeyboardHeight);
+        builder.setOptions(false /* shortcutImeEnabled */, false /* showsVoiceInputKey */,
+                false /* languageSwitchKeyEnabled */);
+        mEmojiCategory = new EmojiCategory(PreferenceManager.getDefaultSharedPreferences(context),
+                context.getResources(), builder.build());
+        mDeleteKeyOnTouchListener = new DeleteKeyOnTouchListener(context);
+    }
+
+    @Override
+    protected void onMeasure(final int widthMeasureSpec, final int heightMeasureSpec) {
+        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
+        final Resources res = getContext().getResources();
+        // The main keyboard expands to the entire this {@link KeyboardView}.
+        final int width = ResourceUtils.getDefaultKeyboardWidth(res)
+                + getPaddingLeft() + getPaddingRight();
+        final int height = ResourceUtils.getDefaultKeyboardHeight(res)
+                + res.getDimensionPixelSize(R.dimen.config_suggestions_strip_height)
+                + getPaddingTop() + getPaddingBottom();
+        setMeasuredDimension(width, height);
+    }
+
+    private void addTab(final TabHost host, final int categoryId) {
+        final String tabId = mEmojiCategory.getCategoryName(categoryId, 0 /* categoryPageId */);
+        final TabHost.TabSpec tspec = host.newTabSpec(tabId);
+        tspec.setContent(R.id.emoji_keyboard_dummy);
+        if (mEmojiCategory.getCategoryIcon(categoryId) != 0) {
+            final ImageView iconView = (ImageView)LayoutInflater.from(getContext()).inflate(
+                    R.layout.emoji_keyboard_tab_icon, null);
+            iconView.setImageResource(mEmojiCategory.getCategoryIcon(categoryId));
+            iconView.setContentDescription(mEmojiCategory.getAccessibilityDescription(categoryId));
+            tspec.setIndicator(iconView);
+        }
+        if (mEmojiCategory.getCategoryLabel(categoryId) != null) {
+            final TextView textView = (TextView)LayoutInflater.from(getContext()).inflate(
+                    R.layout.emoji_keyboard_tab_label, null);
+            textView.setText(mEmojiCategory.getCategoryLabel(categoryId));
+            textView.setTypeface(Typeface.DEFAULT_BOLD);
+            textView.setContentDescription(mEmojiCategory.getAccessibilityDescription(categoryId));
+            if (mTabLabelColor != null) {
+                textView.setTextColor(mTabLabelColor);
+            }
+            tspec.setIndicator(textView);
+        }
+        host.addTab(tspec);
+    }
+
+    @Override
+    protected void onFinishInflate() {
+        mTabHost = (TabHost)findViewById(R.id.emoji_category_tabhost);
+        mTabHost.setup();
+        for (final EmojiCategory.CategoryProperties properties
+                : mEmojiCategory.getShownCategories()) {
+            addTab(mTabHost, properties.mCategoryId);
+        }
+        mTabHost.setOnTabChangedListener(this);
+        mTabHost.getTabWidget().setStripEnabled(true);
+
+        mEmojiPalettesAdapter = new EmojiPalettesAdapter(mEmojiCategory, this);
+
+        mEmojiPager = (ViewPager)findViewById(R.id.emoji_keyboard_pager);
+        mEmojiPager.setAdapter(mEmojiPalettesAdapter);
+        mEmojiPager.setOnPageChangeListener(this);
+        mEmojiPager.setOffscreenPageLimit(0);
+        mEmojiPager.setPersistentDrawingCache(PERSISTENT_NO_CACHE);
+        mEmojiLayoutParams.setPagerProperties(mEmojiPager);
+
+        mEmojiCategoryPageIndicatorView =
+                (EmojiCategoryPageIndicatorView)findViewById(R.id.emoji_category_page_id_view);
+        mEmojiLayoutParams.setCategoryPageIdViewProperties(mEmojiCategoryPageIndicatorView);
+
+        setCurrentCategoryId(mEmojiCategory.getCurrentCategoryId(), true /* force */);
+
+        final LinearLayout actionBar = (LinearLayout)findViewById(R.id.emoji_action_bar);
+        mEmojiLayoutParams.setActionBarProperties(actionBar);
+
+        // deleteKey depends only on OnTouchListener.
+        mDeleteKey = (ImageButton)findViewById(R.id.emoji_keyboard_delete);
+        mDeleteKey.setBackgroundResource(mFunctionalKeyBackgroundId);
+        mDeleteKey.setTag(Constants.CODE_DELETE);
+        mDeleteKey.setOnTouchListener(mDeleteKeyOnTouchListener);
+
+        // {@link #mAlphabetKeyLeft}, {@link #mAlphabetKeyRight, and spaceKey depend on
+        // {@link View.OnClickListener} as well as {@link View.OnTouchListener}.
+        // {@link View.OnTouchListener} is used as the trigger of key-press, while
+        // {@link View.OnClickListener} is used as the trigger of key-release which does not occur
+        // if the event is canceled by moving off the finger from the view.
+        // The text on alphabet keys are set at
+        // {@link #startEmojiPalettes(String,int,float,Typeface)}.
+        mAlphabetKeyLeft = (TextView)findViewById(R.id.emoji_keyboard_alphabet_left);
+        mAlphabetKeyLeft.setBackgroundResource(mFunctionalKeyBackgroundId);
+        mAlphabetKeyLeft.setTag(Constants.CODE_ALPHA_FROM_EMOJI);
+        mAlphabetKeyLeft.setOnTouchListener(this);
+        mAlphabetKeyLeft.setOnClickListener(this);
+        mAlphabetKeyRight = (TextView)findViewById(R.id.emoji_keyboard_alphabet_right);
+        mAlphabetKeyRight.setBackgroundResource(mFunctionalKeyBackgroundId);
+        mAlphabetKeyRight.setTag(Constants.CODE_ALPHA_FROM_EMOJI);
+        mAlphabetKeyRight.setOnTouchListener(this);
+        mAlphabetKeyRight.setOnClickListener(this);
+        mSpacebar = (ImageButton)findViewById(R.id.emoji_keyboard_space);
+        mSpacebar.setBackgroundResource(mSpacebarBackgroundId);
+        mSpacebar.setTag(Constants.CODE_SPACE);
+        mSpacebar.setOnTouchListener(this);
+        mSpacebar.setOnClickListener(this);
+        mEmojiLayoutParams.setKeyProperties(mSpacebar);
+    }
+
+    @Override
+    public boolean dispatchTouchEvent(final MotionEvent ev) {
+        // Add here to the stack trace to nail down the {@link IllegalArgumentException} exception
+        // in MotionEvent that sporadically happens.
+        // TODO: Remove this override method once the issue has been addressed.
+        return super.dispatchTouchEvent(ev);
+    }
+
+    @Override
+    public void onTabChanged(final String tabId) {
+        final int categoryId = mEmojiCategory.getCategoryId(tabId);
+        setCurrentCategoryId(categoryId, false /* force */);
+        updateEmojiCategoryPageIdView();
+    }
+
+    @Override
+    public void onPageSelected(final int position) {
+        final Pair<Integer, Integer> newPos =
+                mEmojiCategory.getCategoryIdAndPageIdFromPagePosition(position);
+        setCurrentCategoryId(newPos.first /* categoryId */, false /* force */);
+        mEmojiCategory.setCurrentCategoryPageId(newPos.second /* categoryPageId */);
+        updateEmojiCategoryPageIdView();
+        mCurrentPagerPosition = position;
+    }
+
+    @Override
+    public void onPageScrollStateChanged(final int state) {
+        // Ignore this message. Only want the actual page selected.
+    }
+
+    @Override
+    public void onPageScrolled(final int position, final float positionOffset,
+            final int positionOffsetPixels) {
+        mEmojiPalettesAdapter.onPageScrolled();
+        final Pair<Integer, Integer> newPos =
+                mEmojiCategory.getCategoryIdAndPageIdFromPagePosition(position);
+        final int newCategoryId = newPos.first;
+        final int newCategorySize = mEmojiCategory.getCategoryPageSize(newCategoryId);
+        final int currentCategoryId = mEmojiCategory.getCurrentCategoryId();
+        final int currentCategoryPageId = mEmojiCategory.getCurrentCategoryPageId();
+        final int currentCategorySize = mEmojiCategory.getCurrentCategoryPageSize();
+        if (newCategoryId == currentCategoryId) {
+            mEmojiCategoryPageIndicatorView.setCategoryPageId(
+                    newCategorySize, newPos.second, positionOffset);
+        } else if (newCategoryId > currentCategoryId) {
+            mEmojiCategoryPageIndicatorView.setCategoryPageId(
+                    currentCategorySize, currentCategoryPageId, positionOffset);
+        } else if (newCategoryId < currentCategoryId) {
+            mEmojiCategoryPageIndicatorView.setCategoryPageId(
+                    currentCategorySize, currentCategoryPageId, positionOffset - 1);
+        }
+    }
+
+    /**
+     * Called from {@link EmojiPageKeyboardView} through {@link android.view.View.OnTouchListener}
+     * interface to handle touch events from View-based elements such as the space bar.
+     * Note that this method is used only for observing {@link MotionEvent#ACTION_DOWN} to trigger
+     * {@link KeyboardActionListener#onPressKey}. {@link KeyboardActionListener#onReleaseKey} will
+     * be covered by {@link #onClick} as long as the event is not canceled.
+     */
+    @Override
+    public boolean onTouch(final View v, final MotionEvent event) {
+        if (event.getActionMasked() != MotionEvent.ACTION_DOWN) {
+            return false;
+        }
+        final Object tag = v.getTag();
+        if (!(tag instanceof Integer)) {
+            return false;
+        }
+        final int code = (Integer) tag;
+        mKeyboardActionListener.onPressKey(
+                code, 0 /* repeatCount */, true /* isSinglePointer */);
+        // It's important to return false here. Otherwise, {@link #onClick} and touch-down visual
+        // feedback stop working.
+        return false;
+    }
+
+    /**
+     * Called from {@link EmojiPageKeyboardView} through {@link android.view.View.OnClickListener}
+     * interface to handle non-canceled touch-up events from View-based elements such as the space
+     * bar.
+     */
+    @Override
+    public void onClick(View v) {
+        final Object tag = v.getTag();
+        if (!(tag instanceof Integer)) {
+            return;
+        }
+        final int code = (Integer) tag;
+        mKeyboardActionListener.onCodeInput(code, NOT_A_COORDINATE, NOT_A_COORDINATE,
+                false /* isKeyRepeat */);
+        mKeyboardActionListener.onReleaseKey(code, false /* withSliding */);
+    }
+
+    /**
+     * Called from {@link EmojiPageKeyboardView} through
+     * {@link com.android.inputmethod.keyboard.emoji.EmojiPageKeyboardView.OnKeyEventListener}
+     * interface to handle touch events from non-View-based elements such as Emoji buttons.
+     */
+    @Override
+    public void onPressKey(final Key key) {
+        final int code = key.getCode();
+        mKeyboardActionListener.onPressKey(code, 0 /* repeatCount */, true /* isSinglePointer */);
+    }
+
+    /**
+     * Called from {@link EmojiPageKeyboardView} through
+     * {@link com.android.inputmethod.keyboard.emoji.EmojiPageKeyboardView.OnKeyEventListener}
+     * interface to handle touch events from non-View-based elements such as Emoji buttons.
+     */
+    @Override
+    public void onReleaseKey(final Key key) {
+        mEmojiPalettesAdapter.addRecentKey(key);
+        mEmojiCategory.saveLastTypedCategoryPage();
+        final int code = key.getCode();
+        if (code == Constants.CODE_OUTPUT_TEXT) {
+            mKeyboardActionListener.onTextInput(key.getOutputText());
+        } else {
+            mKeyboardActionListener.onCodeInput(code, NOT_A_COORDINATE, NOT_A_COORDINATE,
+                    false /* isKeyRepeat */);
+        }
+        mKeyboardActionListener.onReleaseKey(code, false /* withSliding */);
+    }
+
+    public void setHardwareAcceleratedDrawingEnabled(final boolean enabled) {
+        if (!enabled) return;
+        // TODO: Should use LAYER_TYPE_SOFTWARE when hardware acceleration is off?
+        setLayerType(LAYER_TYPE_HARDWARE, null);
+    }
+
+    private static void setupAlphabetKey(final TextView alphabetKey, final String label,
+            final KeyDrawParams params) {
+        alphabetKey.setText(label);
+        alphabetKey.setTextColor(params.mTextColor);
+        alphabetKey.setTextSize(TypedValue.COMPLEX_UNIT_PX, params.mLabelSize);
+        alphabetKey.setTypeface(params.mTypeface);
+    }
+
+    public void startEmojiPalettes(final String switchToAlphaLabel,
+            final KeyVisualAttributes keyVisualAttr, final KeyboardIconsSet iconSet) {
+        mDeleteKey.setImageDrawable(iconSet.getIconDrawable(KeyboardIconsSet.NAME_DELETE_KEY));
+        mSpacebar.setImageDrawable(iconSet.getIconDrawable(KeyboardIconsSet.NAME_SPACE_KEY));
+        final KeyDrawParams params = new KeyDrawParams();
+        params.updateParams(mEmojiLayoutParams.getActionBarHeight(), keyVisualAttr);
+        setupAlphabetKey(mAlphabetKeyLeft, switchToAlphaLabel, params);
+        setupAlphabetKey(mAlphabetKeyRight, switchToAlphaLabel, params);
+        mEmojiPager.setAdapter(mEmojiPalettesAdapter);
+        mEmojiPager.setCurrentItem(mCurrentPagerPosition);
+    }
+
+    public void stopEmojiPalettes() {
+        mEmojiPalettesAdapter.flushPendingRecentKeys();
+        mEmojiPager.setAdapter(null);
+    }
+
+    public void setKeyboardActionListener(final KeyboardActionListener listener) {
+        mKeyboardActionListener = listener;
+        mDeleteKeyOnTouchListener.setKeyboardActionListener(mKeyboardActionListener);
+    }
+
+    private void updateEmojiCategoryPageIdView() {
+        if (mEmojiCategoryPageIndicatorView == null) {
+            return;
+        }
+        mEmojiCategoryPageIndicatorView.setCategoryPageId(
+                mEmojiCategory.getCurrentCategoryPageSize(),
+                mEmojiCategory.getCurrentCategoryPageId(), 0.0f /* offset */);
+    }
+
+    private void setCurrentCategoryId(final int categoryId, final boolean force) {
+        final int oldCategoryId = mEmojiCategory.getCurrentCategoryId();
+        if (oldCategoryId == categoryId && !force) {
+            return;
+        }
+
+        if (oldCategoryId == EmojiCategory.ID_RECENTS) {
+            // Needs to save pending updates for recent keys when we get out of the recents
+            // category because we don't want to move the recent emojis around while the user
+            // is in the recents category.
+            mEmojiPalettesAdapter.flushPendingRecentKeys();
+        }
+
+        mEmojiCategory.setCurrentCategoryId(categoryId);
+        final int newTabId = mEmojiCategory.getTabIdFromCategoryId(categoryId);
+        final int newCategoryPageId = mEmojiCategory.getPageIdFromCategoryId(categoryId);
+        if (force || mEmojiCategory.getCategoryIdAndPageIdFromPagePosition(
+                mEmojiPager.getCurrentItem()).first != categoryId) {
+            mEmojiPager.setCurrentItem(newCategoryPageId, false /* smoothScroll */);
+        }
+        if (force || mTabHost.getCurrentTab() != newTabId) {
+            mTabHost.setCurrentTab(newTabId);
+        }
+    }
+
+    private static class DeleteKeyOnTouchListener implements OnTouchListener {
+        static final long MAX_REPEAT_COUNT_TIME = TimeUnit.SECONDS.toMillis(30);
+        final int mDeleteKeyPressedBackgroundColor;
+        final long mKeyRepeatStartTimeout;
+        final long mKeyRepeatInterval;
+
+        public DeleteKeyOnTouchListener(Context context) {
+            final Resources res = context.getResources();
+            mDeleteKeyPressedBackgroundColor =
+                    res.getColor(R.color.emoji_key_pressed_background_color);
+            mKeyRepeatStartTimeout = res.getInteger(R.integer.config_key_repeat_start_timeout);
+            mKeyRepeatInterval = res.getInteger(R.integer.config_key_repeat_interval);
+            mTimer = new CountDownTimer(MAX_REPEAT_COUNT_TIME, mKeyRepeatInterval) {
+                @Override
+                public void onTick(long millisUntilFinished) {
+                    final long elapsed = MAX_REPEAT_COUNT_TIME - millisUntilFinished;
+                    if (elapsed < mKeyRepeatStartTimeout) {
+                        return;
+                    }
+                    onKeyRepeat();
+                }
+                @Override
+                public void onFinish() {
+                    onKeyRepeat();
+                }
+            };
+        }
+
+        /** Key-repeat state. */
+        private static final int KEY_REPEAT_STATE_INITIALIZED = 0;
+        // The key is touched but auto key-repeat is not started yet.
+        private static final int KEY_REPEAT_STATE_KEY_DOWN = 1;
+        // At least one key-repeat event has already been triggered and the key is not released.
+        private static final int KEY_REPEAT_STATE_KEY_REPEAT = 2;
+
+        private KeyboardActionListener mKeyboardActionListener =
+                KeyboardActionListener.EMPTY_LISTENER;
+
+        // TODO: Do the same things done in PointerTracker
+        private final CountDownTimer mTimer;
+        private int mState = KEY_REPEAT_STATE_INITIALIZED;
+        private int mRepeatCount = 0;
+
+        public void setKeyboardActionListener(final KeyboardActionListener listener) {
+            mKeyboardActionListener = listener;
+        }
+
+        @Override
+        public boolean onTouch(final View v, final MotionEvent event) {
+            switch (event.getActionMasked()) {
+            case MotionEvent.ACTION_DOWN:
+                onTouchDown(v);
+                return true;
+            case MotionEvent.ACTION_MOVE:
+                final float x = event.getX();
+                final float y = event.getY();
+                if (x < 0.0f || v.getWidth() < x || y < 0.0f || v.getHeight() < y) {
+                    // Stop generating key events once the finger moves away from the view area.
+                    onTouchCanceled(v);
+                }
+                return true;
+            case MotionEvent.ACTION_CANCEL:
+            case MotionEvent.ACTION_UP:
+                onTouchUp(v);
+                return true;
+            }
+            return false;
+        }
+
+        private void handleKeyDown() {
+            mKeyboardActionListener.onPressKey(
+                    Constants.CODE_DELETE, mRepeatCount, true /* isSinglePointer */);
+        }
+
+        private void handleKeyUp() {
+            mKeyboardActionListener.onCodeInput(Constants.CODE_DELETE,
+                    NOT_A_COORDINATE, NOT_A_COORDINATE, false /* isKeyRepeat */);
+            mKeyboardActionListener.onReleaseKey(
+                    Constants.CODE_DELETE, false /* withSliding */);
+            ++mRepeatCount;
+        }
+
+        private void onTouchDown(final View v) {
+            mTimer.cancel();
+            mRepeatCount = 0;
+            handleKeyDown();
+            v.setBackgroundColor(mDeleteKeyPressedBackgroundColor);
+            mState = KEY_REPEAT_STATE_KEY_DOWN;
+            mTimer.start();
+        }
+
+        private void onTouchUp(final View v) {
+            mTimer.cancel();
+            if (mState == KEY_REPEAT_STATE_KEY_DOWN) {
+                handleKeyUp();
+            }
+            v.setBackgroundColor(Color.TRANSPARENT);
+            mState = KEY_REPEAT_STATE_INITIALIZED;
+        }
+
+        private void onTouchCanceled(final View v) {
+            mTimer.cancel();
+            v.setBackgroundColor(Color.TRANSPARENT);
+            mState = KEY_REPEAT_STATE_INITIALIZED;
+        }
+
+        // Called by {@link #mTimer} in the UI thread as an auto key-repeat signal.
+        void onKeyRepeat() {
+            switch (mState) {
+            case KEY_REPEAT_STATE_INITIALIZED:
+                // Basically this should not happen.
+                break;
+            case KEY_REPEAT_STATE_KEY_DOWN:
+                // Do not call {@link #handleKeyDown} here because it has already been called
+                // in {@link #onTouchDown}.
+                handleKeyUp();
+                mState = KEY_REPEAT_STATE_KEY_REPEAT;
+                break;
+            case KEY_REPEAT_STATE_KEY_REPEAT:
+                handleKeyDown();
+                handleKeyUp();
+                break;
+            }
+        }
+    }
+}
diff --git a/java/src/com/android/inputmethod/keyboard/internal/KeyboardIconsSet.java b/java/src/com/android/inputmethod/keyboard/internal/KeyboardIconsSet.java
index 65d6a56..b5a9480 100644
--- a/java/src/com/android/inputmethod/keyboard/internal/KeyboardIconsSet.java
+++ b/java/src/com/android/inputmethod/keyboard/internal/KeyboardIconsSet.java
@@ -138,6 +138,10 @@
         throw new RuntimeException("unknown icon name: " + name);
     }
 
+    public Drawable getIconDrawable(final String name) {
+        return getIconDrawable(getIconId(name));
+    }
+
     public Drawable getIconDrawable(final int iconId) {
         if (isValidIconId(iconId)) {
             return mIcons[iconId];
diff --git a/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java b/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
index 6818c15..e323f0a 100644
--- a/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
+++ b/java/src/com/android/inputmethod/latin/ExpandableBinaryDictionary.java
@@ -607,6 +607,7 @@
                 Log.d(TAG, "Dump dictionary: " + mDictName);
                 try {
                     final DictionaryHeader header = mBinaryDictionary.getHeader();
+                    Log.d(TAG, "Format version: " + mBinaryDictionary.getFormatVersion());
                     Log.d(TAG, CombinedFormatUtils.formatAttributeMap(
                             header.mDictionaryOptions.mAttributes));
                 } catch (final UnsupportedFormatException e) {
diff --git a/java/src/com/android/inputmethod/latin/LatinIME.java b/java/src/com/android/inputmethod/latin/LatinIME.java
index 8a2ed10..3751a3c 100644
--- a/java/src/com/android/inputmethod/latin/LatinIME.java
+++ b/java/src/com/android/inputmethod/latin/LatinIME.java
@@ -84,6 +84,7 @@
 import com.android.inputmethod.latin.utils.CoordinateUtils;
 import com.android.inputmethod.latin.utils.DialogUtils;
 import com.android.inputmethod.latin.utils.DistracterFilter;
+import com.android.inputmethod.latin.utils.DistracterFilterUtils;
 import com.android.inputmethod.latin.utils.ImportantNoticeUtils;
 import com.android.inputmethod.latin.utils.IntentUtils;
 import com.android.inputmethod.latin.utils.JniUtils;
@@ -1745,7 +1746,8 @@
 
     @UsedForTesting
     /* package for test */ DistracterFilter createDistracterFilter() {
-        return DistracterFilter.createDistracterFilter(mInputLogic.mSuggest, mKeyboardSwitcher);
+        return DistracterFilterUtils.createDistracterFilter(
+                mInputLogic.mSuggest, mKeyboardSwitcher);
     }
 
     public void dumpDictionaryForDebug(final String dictName) {
diff --git a/java/src/com/android/inputmethod/latin/WordComposer.java b/java/src/com/android/inputmethod/latin/WordComposer.java
index cdee496..ac69729 100644
--- a/java/src/com/android/inputmethod/latin/WordComposer.java
+++ b/java/src/com/android/inputmethod/latin/WordComposer.java
@@ -80,7 +80,7 @@
     private boolean mIsFirstCharCapitalized;
 
     public WordComposer() {
-        mCombinerChain = new CombinerChain();
+        mCombinerChain = new CombinerChain("");
         mEvents = CollectionUtils.newArrayList();
         mAutoCorrection = null;
         mIsResumed = false;
@@ -92,18 +92,17 @@
     }
 
     /**
-     * Restart input with a new combining spec.
+     * Restart the combiners, possibly with a new spec.
      * @param combiningSpec The spec string for combining. This is found in the extra value.
      */
-    public void restart(final String combiningSpec) {
+    public void restartCombining(final String combiningSpec) {
         final String nonNullCombiningSpec = null == combiningSpec ? "" : combiningSpec;
-        if (nonNullCombiningSpec.equals(mCombiningSpec)) {
-            mCombinerChain.reset();
-        } else {
-            mCombinerChain = new CombinerChain(CombinerChain.createCombiners(nonNullCombiningSpec));
+        if (!nonNullCombiningSpec.equals(mCombiningSpec)) {
+            mCombinerChain = new CombinerChain(
+                    mCombinerChain.getComposingWordWithCombiningFeedback().toString(),
+                    CombinerChain.createCombiners(nonNullCombiningSpec));
             mCombiningSpec = nonNullCombiningSpec;
         }
-        reset();
     }
 
     /**
diff --git a/java/src/com/android/inputmethod/latin/inputlogic/InputLogic.java b/java/src/com/android/inputmethod/latin/inputlogic/InputLogic.java
index 8b795b8..ea58abc 100644
--- a/java/src/com/android/inputmethod/latin/inputlogic/InputLogic.java
+++ b/java/src/com/android/inputmethod/latin/inputlogic/InputLogic.java
@@ -127,7 +127,7 @@
     public void startInput(final boolean restarting, final EditorInfo editorInfo,
             final String combiningSpec) {
         mEnteredText = null;
-        mWordComposer.restart(combiningSpec);
+        mWordComposer.restartCombining(combiningSpec);
         resetComposingState(true /* alsoResetLastComposedWord */);
         mDeleteCount = 0;
         mSpaceState = SpaceState.NONE;
@@ -150,7 +150,7 @@
      * @param combiningSpec the spec string for the combining rules
      */
     public void onSubtypeChanged(final String combiningSpec) {
-        mWordComposer.restart(combiningSpec);
+        mWordComposer.restartCombining(combiningSpec);
     }
 
     /**
@@ -936,7 +936,11 @@
             } else {
                 mWordComposer.processEvent(inputTransaction.mEvent);
             }
-            mConnection.setComposingText(getTextWithUnderline(mWordComposer.getTypedWord()), 1);
+            if (mWordComposer.isComposingWord()) {
+                mConnection.setComposingText(getTextWithUnderline(mWordComposer.getTypedWord()), 1);
+            } else {
+                mConnection.commitText("", 1);
+            }
             inputTransaction.setRequiresUpdateSuggestions();
         } else {
             if (mLastComposedWord.canRevertCommit()) {
diff --git a/java/src/com/android/inputmethod/latin/makedict/FormatSpec.java b/java/src/com/android/inputmethod/latin/makedict/FormatSpec.java
index 613ff2b..f5f072b 100644
--- a/java/src/com/android/inputmethod/latin/makedict/FormatSpec.java
+++ b/java/src/com/android/inputmethod/latin/makedict/FormatSpec.java
@@ -193,8 +193,9 @@
     // Dictionary version used for testing.
     public static final int VERSION4_ONLY_FOR_TESTING = 399;
     public static final int VERSION4 = 401;
+    public static final int VERSION4_DEV = 402;
     static final int MINIMUM_SUPPORTED_VERSION = VERSION2;
-    static final int MAXIMUM_SUPPORTED_VERSION = VERSION4;
+    static final int MAXIMUM_SUPPORTED_VERSION = VERSION4_DEV;
 
     // TODO: Make this value adaptative to content data, store it in the header, and
     // use it in the reading code.
diff --git a/java/src/com/android/inputmethod/latin/utils/DistracterFilter.java b/java/src/com/android/inputmethod/latin/utils/DistracterFilter.java
index 55cbf79..0a03799 100644
--- a/java/src/com/android/inputmethod/latin/utils/DistracterFilter.java
+++ b/java/src/com/android/inputmethod/latin/utils/DistracterFilter.java
@@ -17,8 +17,6 @@
 package com.android.inputmethod.latin.utils;
 
 import com.android.inputmethod.keyboard.Keyboard;
-import com.android.inputmethod.keyboard.KeyboardSwitcher;
-import com.android.inputmethod.keyboard.MainKeyboardView;
 import com.android.inputmethod.latin.Constants;
 import com.android.inputmethod.latin.Suggest;
 import com.android.inputmethod.latin.Suggest.OnGetSuggestedWordsCallback;
@@ -54,18 +52,6 @@
         mKeyboard = keyboard;
     }
 
-    public static DistracterFilter createDistracterFilter(final Suggest suggest,
-            final KeyboardSwitcher keyboardSwitcher) {
-        final MainKeyboardView mainKeyboardView = keyboardSwitcher.getMainKeyboardView();
-        // TODO: Create Keyboard when mainKeyboardView is null.
-        // TODO: Figure out the most reasonable keyboard for the filter. Refer to the
-        // spellchecker's logic.
-        final Keyboard keyboard = (mainKeyboardView != null) ?
-                mainKeyboardView.getKeyboard() : null;
-        final DistracterFilter distracterFilter = new DistracterFilter(suggest, keyboard);
-        return distracterFilter;
-    }
-
     private static boolean suggestionExceedsDistracterThreshold(
             final SuggestedWordInfo suggestion, final String consideredWord,
             final float distracterThreshold) {
@@ -90,19 +76,14 @@
      */
     public boolean isDistracterToWordsInDictionaries(final String prevWord,
             final String testedWord) {
-        if (mSuggest == null) {
+        if (mSuggest == null || mKeyboard == null) {
             return false;
         }
 
         final WordComposer composer = new WordComposer();
         final int[] codePoints = StringUtils.toCodePointArray(testedWord);
         final int[] coordinates;
-        if (null == mKeyboard) {
-            coordinates = CoordinateUtils.newCoordinateArray(codePoints.length,
-                    Constants.NOT_A_COORDINATE, Constants.NOT_A_COORDINATE);
-        } else {
-            coordinates = mKeyboard.getCoordinates(codePoints);
-        }
+        coordinates = mKeyboard.getCoordinates(codePoints);
         composer.setComposingWord(codePoints, coordinates, prevWord);
 
         final int trailingSingleQuotesCount = composer.trailingSingleQuotesCount();
diff --git a/java/src/com/android/inputmethod/latin/utils/DistracterFilterUtils.java b/java/src/com/android/inputmethod/latin/utils/DistracterFilterUtils.java
new file mode 100644
index 0000000..df07f97
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/utils/DistracterFilterUtils.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.inputmethod.latin.utils;
+
+import com.android.inputmethod.keyboard.Keyboard;
+import com.android.inputmethod.keyboard.KeyboardSwitcher;
+import com.android.inputmethod.keyboard.MainKeyboardView;
+import com.android.inputmethod.latin.Suggest;
+
+public class DistracterFilterUtils {
+    private DistracterFilterUtils() {
+        // This utility class is not publicly instantiable.
+    }
+
+    public static final DistracterFilter createDistracterFilter(final Suggest suggest,
+            final KeyboardSwitcher keyboardSwitcher) {
+        final MainKeyboardView mainKeyboardView = keyboardSwitcher.getMainKeyboardView();
+        // TODO: Create Keyboard when mainKeyboardView is null.
+        // TODO: Figure out the most reasonable keyboard for the filter. Refer to the
+        // spellchecker's logic.
+        final Keyboard keyboard = (mainKeyboardView != null) ?
+                mainKeyboardView.getKeyboard() : null;
+        final DistracterFilter distracterFilter = new DistracterFilter(suggest, keyboard);
+        return distracterFilter;
+    }
+}
diff --git a/native/jni/CleanupNativeFileList.mk b/native/jni/CleanupNativeFileList.mk
index 1738f8c..eed6f1e 100644
--- a/native/jni/CleanupNativeFileList.mk
+++ b/native/jni/CleanupNativeFileList.mk
@@ -13,6 +13,7 @@
 # limitations under the License.
 
 LATIN_IME_CORE_SRC_FILES :=
+LATIN_IME_CORE_SRC_FILES_BACKWARD_V401 :=
 LATIN_IME_CORE_TEST_FILES :=
 LATIN_IME_JNI_SRC_FILES :=
 LATIN_IME_SRC_DIR :=
diff --git a/native/jni/NativeFileList.mk b/native/jni/NativeFileList.mk
index 6ccfec9..cb337e6 100644
--- a/native/jni/NativeFileList.mk
+++ b/native/jni/NativeFileList.mk
@@ -95,9 +95,31 @@
     $(addprefix utils/, \
         autocorrection_threshold_utils.cpp \
         char_utils.cpp \
+        jni_data_utils.cpp \
         log_utils.cpp \
         time_keeper.cpp)
 
+LATIN_IME_CORE_SRC_FILES_BACKWARD_V401 := \
+    $(addprefix suggest/policyimpl/dictionary/structure/backward/v401/, \
+        ver4_dict_buffers.cpp \
+        ver4_dict_constants.cpp \
+        ver4_patricia_trie_node_reader.cpp \
+        ver4_patricia_trie_node_writer.cpp \
+        ver4_patricia_trie_policy.cpp \
+        ver4_patricia_trie_reading_utils.cpp \
+        ver4_patricia_trie_writing_helper.cpp \
+        ver4_pt_node_array_reader.cpp) \
+    $(addprefix suggest/policyimpl/dictionary/structure/backward/v401/content/, \
+        bigram_dict_content.cpp \
+        probability_dict_content.cpp \
+        shortcut_dict_content.cpp \
+        sparse_table_dict_content.cpp \
+        terminal_position_lookup_table.cpp) \
+    $(addprefix suggest/policyimpl/dictionary/structure/backward/v401/bigram/, \
+        ver4_bigram_list_policy.cpp)
+
+LATIN_IME_CORE_SRC_FILES += $(LATIN_IME_CORE_SRC_FILES_BACKWARD_V401)
+
 LATIN_IME_CORE_TEST_FILES := \
     defines_test.cpp \
     suggest/core/layout/normal_distribution_2d_test.cpp \
diff --git a/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp b/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
index a55b2da..18b78c4 100644
--- a/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
+++ b/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
@@ -136,10 +136,9 @@
     if (!dictionary) return;
     const DictionaryHeaderStructurePolicy *const headerPolicy =
             dictionary->getDictionaryStructurePolicy()->getHeaderStructurePolicy();
-    const int headerSize = headerPolicy->getSize();
-    env->SetIntArrayRegion(outHeaderSize, 0 /* start */, 1 /* len */, &headerSize);
-    const int formatVersion = headerPolicy->getFormatVersionNumber();
-    env->SetIntArrayRegion(outFormatVersion, 0 /* start */, 1 /* len */, &formatVersion);
+    JniDataUtils::putIntToArray(env, outHeaderSize, 0 /* index */, headerPolicy->getSize());
+    JniDataUtils::putIntToArray(env, outFormatVersion, 0 /* index */,
+            headerPolicy->getFormatVersionNumber());
     // Output attribute map
     jclass arrayListClass = env->FindClass("java/util/ArrayList");
     jmethodID addMethodId = env->GetMethodID(arrayListClass, "add", "(Ljava/lang/Object;)Z");
@@ -149,14 +148,16 @@
             it != attributeMap->end(); ++it) {
         // Output key
         jintArray keyCodePointArray = env->NewIntArray(it->first.size());
-        env->SetIntArrayRegion(
-                keyCodePointArray, 0 /* start */, it->first.size(), &it->first.at(0));
+        JniDataUtils::outputCodePoints(env, keyCodePointArray, 0 /* start */,
+                it->first.size(), it->first.data(), it->first.size(),
+                false /* needsNullTermination */);
         env->CallBooleanMethod(outAttributeKeys, addMethodId, keyCodePointArray);
         env->DeleteLocalRef(keyCodePointArray);
         // Output value
         jintArray valueCodePointArray = env->NewIntArray(it->second.size());
-        env->SetIntArrayRegion(
-                valueCodePointArray, 0 /* start */, it->second.size(), &it->second.at(0));
+        JniDataUtils::outputCodePoints(env, valueCodePointArray, 0 /* start */,
+                it->second.size(), it->second.data(), it->second.size(),
+                false /* needsNullTermination */);
         env->CallBooleanMethod(outAttributeValues, addMethodId, valueCodePointArray);
         env->DeleteLocalRef(valueCodePointArray);
     }
@@ -182,8 +183,7 @@
         jfloatArray inOutLanguageWeight) {
     Dictionary *dictionary = reinterpret_cast<Dictionary *>(dict);
     // Assign 0 to outSuggestionCount here in case of returning earlier in this method.
-    int count = 0;
-    env->SetIntArrayRegion(outSuggestionCount, 0, 1 /* len */, &count);
+    JniDataUtils::putIntToArray(env, outSuggestionCount, 0 /* index */, 0);
     if (!dictionary) {
         return;
     }
@@ -300,7 +300,9 @@
     int wordCodePoints[outCodePointsLength];
     memset(wordCodePoints, 0, sizeof(wordCodePoints));
     const int nextToken = dictionary->getNextWordAndNextToken(token, wordCodePoints);
-    env->SetIntArrayRegion(outCodePoints, 0, outCodePointsLength, wordCodePoints);
+    JniDataUtils::outputCodePoints(env, outCodePoints, 0 /* start */,
+            MAX_WORD_LENGTH /* maxLength */, wordCodePoints, outCodePointsLength,
+            false /* needsNullTermination */);
     return nextToken;
 }
 
diff --git a/native/jni/src/suggest/core/dictionary/property/word_property.cpp b/native/jni/src/suggest/core/dictionary/property/word_property.cpp
index 95608dc..6f5f808 100644
--- a/native/jni/src/suggest/core/dictionary/property/word_property.cpp
+++ b/native/jni/src/suggest/core/dictionary/property/word_property.cpp
@@ -16,14 +16,17 @@
 
 #include "suggest/core/dictionary/property/word_property.h"
 
+#include "utils/jni_data_utils.h"
+
 namespace latinime {
 
 void WordProperty::outputProperties(JNIEnv *const env, jintArray outCodePoints,
         jbooleanArray outFlags, jintArray outProbabilityInfo, jobject outBigramTargets,
         jobject outBigramProbabilities, jobject outShortcutTargets,
         jobject outShortcutProbabilities) const {
-    env->SetIntArrayRegion(outCodePoints, 0 /* start */, mCodePoints.size(), &mCodePoints[0]);
-
+    JniDataUtils::outputCodePoints(env, outCodePoints, 0 /* start */,
+            MAX_WORD_LENGTH /* maxLength */, mCodePoints.data(), mCodePoints.size(),
+            false /* needsNullTermination */);
     jboolean flags[] = {mUnigramProperty.isNotAWord(), mUnigramProperty.isBlacklisted(),
             !mBigrams.empty(), mUnigramProperty.hasShortcuts()};
     env->SetBooleanArrayRegion(outFlags, 0 /* start */, NELEMS(flags), flags);
@@ -41,8 +44,9 @@
     for (const auto &bigramProperty : mBigrams) {
         const std::vector<int> *const word1CodePoints = bigramProperty.getTargetCodePoints();
         jintArray bigramWord1CodePointArray = env->NewIntArray(word1CodePoints->size());
-        env->SetIntArrayRegion(bigramWord1CodePointArray, 0 /* start */,
-                word1CodePoints->size(), word1CodePoints->data());
+        JniDataUtils::outputCodePoints(env, bigramWord1CodePointArray, 0 /* start */,
+                word1CodePoints->size(), word1CodePoints->data(), word1CodePoints->size(),
+                false /* needsNullTermination */);
         env->CallBooleanMethod(outBigramTargets, addMethodId, bigramWord1CodePointArray);
         env->DeleteLocalRef(bigramWord1CodePointArray);
 
@@ -62,6 +66,9 @@
         jintArray shortcutTargetCodePointArray = env->NewIntArray(targetCodePoints->size());
         env->SetIntArrayRegion(shortcutTargetCodePointArray, 0 /* start */,
                 targetCodePoints->size(), targetCodePoints->data());
+        JniDataUtils::outputCodePoints(env, shortcutTargetCodePointArray, 0 /* start */,
+                targetCodePoints->size(), targetCodePoints->data(), targetCodePoints->size(),
+                false /* needsNullTermination */);
         env->CallBooleanMethod(outShortcutTargets, addMethodId, shortcutTargetCodePointArray);
         env->DeleteLocalRef(shortcutTargetCodePointArray);
         jobject integerProbability = env->NewObject(integerClass, intToIntegerConstructorId,
diff --git a/native/jni/src/suggest/core/result/suggestion_results.cpp b/native/jni/src/suggest/core/result/suggestion_results.cpp
index 088a55f..4c10bd0 100644
--- a/native/jni/src/suggest/core/result/suggestion_results.cpp
+++ b/native/jni/src/suggest/core/result/suggestion_results.cpp
@@ -16,6 +16,8 @@
 
 #include "suggest/core/result/suggestion_results.h"
 
+#include "utils/jni_data_utils.h"
+
 namespace latinime {
 
 void SuggestionResults::outputSuggestions(JNIEnv *env, jintArray outSuggestionCount,
@@ -27,31 +29,22 @@
         const SuggestedWord &suggestedWord = mSuggestedWords.top();
         suggestedWord.getCodePointCount();
         const int start = outputIndex * MAX_WORD_LENGTH;
-        env->SetIntArrayRegion(outputCodePointsArray, start, suggestedWord.getCodePointCount(),
-                suggestedWord.getCodePoint());
-        if (suggestedWord.getCodePointCount() < MAX_WORD_LENGTH) {
-            const int terminal = 0;
-            env->SetIntArrayRegion(outputCodePointsArray, start + suggestedWord.getCodePointCount(),
-                    1 /* len */, &terminal);
-        }
-        const int score = suggestedWord.getScore();
-        env->SetIntArrayRegion(outScoresArray, outputIndex, 1 /* len */, &score);
-        const int indexToPartialCommit = suggestedWord.getIndexToPartialCommit();
-        env->SetIntArrayRegion(outSpaceIndicesArray, outputIndex, 1 /* len */,
-                &indexToPartialCommit);
-        const int type = suggestedWord.getType();
-        env->SetIntArrayRegion(outTypesArray, outputIndex, 1 /* len */, &type);
+        JniDataUtils::outputCodePoints(env, outputCodePointsArray, start,
+                MAX_WORD_LENGTH /* maxLength */, suggestedWord.getCodePoint(),
+                suggestedWord.getCodePointCount(), true /* needsNullTermination */);
+        JniDataUtils::putIntToArray(env, outScoresArray, outputIndex, suggestedWord.getScore());
+        JniDataUtils::putIntToArray(env, outSpaceIndicesArray, outputIndex,
+                suggestedWord.getIndexToPartialCommit());
+        JniDataUtils::putIntToArray(env, outTypesArray, outputIndex, suggestedWord.getType());
         if (mSuggestedWords.size() == 1) {
-            const int autoCommitFirstWordConfidence =
-                    suggestedWord.getAutoCommitFirstWordConfidence();
-            env->SetIntArrayRegion(outAutoCommitFirstWordConfidenceArray, 0 /* start */,
-                    1 /* len */, &autoCommitFirstWordConfidence);
+            JniDataUtils::putIntToArray(env, outAutoCommitFirstWordConfidenceArray, 0 /* index */,
+                    suggestedWord.getAutoCommitFirstWordConfidence());
         }
         ++outputIndex;
         mSuggestedWords.pop();
     }
-    env->SetIntArrayRegion(outSuggestionCount, 0 /* start */, 1 /* len */, &outputIndex);
-    env->SetFloatArrayRegion(outLanguageWeight, 0 /* start */, 1 /* len */, &mLanguageWeight);
+    JniDataUtils::putIntToArray(env, outSuggestionCount, 0 /* index */, outputIndex);
+    JniDataUtils::putFloatToArray(env, outLanguageWeight, 0 /* index */, mLanguageWeight);
 }
 
 void SuggestionResults::addPrediction(const int *const codePoints, const int codePointCount,
diff --git a/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.h b/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.h
index da24302..479d151 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/header/header_policy.h
@@ -143,6 +143,8 @@
                 return FormatUtils::VERSION_4_ONLY_FOR_TESTING;
             case FormatUtils::VERSION_4:
                 return FormatUtils::VERSION_4;
+            case FormatUtils::VERSION_4_DEV:
+                return FormatUtils::VERSION_4_DEV;
             default:
                 return FormatUtils::UNKNOWN_VERSION;
         }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/header/header_read_write_utils.cpp b/native/jni/src/suggest/policyimpl/dictionary/header/header_read_write_utils.cpp
index 2a9028a..a8f8f28 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/header/header_read_write_utils.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/header/header_read_write_utils.cpp
@@ -100,6 +100,7 @@
             return false;
         case FormatUtils::VERSION_4_ONLY_FOR_TESTING:
         case FormatUtils::VERSION_4:
+        case FormatUtils::VERSION_4_DEV:
             return buffer->writeUintAndAdvancePosition(version /* data */,
                     HEADER_DICTIONARY_VERSION_SIZE, writingPos);
         default:
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/Readme.txt b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/Readme.txt
new file mode 100644
index 0000000..9e29e83
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/Readme.txt
@@ -0,0 +1 @@
+Files under this directory have been auto generated.
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/bigram/ver4_bigram_list_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/bigram/ver4_bigram_list_policy.cpp
new file mode 100644
index 0000000..7ad072f
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/bigram/ver4_bigram_list_policy.cpp
@@ -0,0 +1,290 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT CHANGE THE LOGIC IN THIS FILE !!!!!
+ * Do not edit this file other than updating policy's interface.
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/bigram/ver4_bigram_list_policy.cpp
+ */
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/bigram/ver4_bigram_list_policy.h"
+
+#include "suggest/core/dictionary/property/bigram_property.h"
+#include "suggest/policyimpl/dictionary/header/header_policy.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/bigram/bigram_list_read_write_utils.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/bigram_dict_content.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h"
+#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+void Ver4BigramListPolicy::getNextBigram(int *const outBigramPos, int *const outProbability,
+        bool *const outHasNext, int *const bigramEntryPos) const {
+    const BigramEntry bigramEntry =
+            mBigramDictContent->getBigramEntryAndAdvancePosition(bigramEntryPos);
+    if (outBigramPos) {
+        // Lookup target PtNode position.
+        *outBigramPos = mTerminalPositionLookupTable->getTerminalPtNodePosition(
+                bigramEntry.getTargetTerminalId());
+    }
+    if (outProbability) {
+        if (bigramEntry.hasHistoricalInfo()) {
+            *outProbability =
+                    ForgettingCurveUtils::decodeProbability(bigramEntry.getHistoricalInfo(),
+                            mHeaderPolicy);
+        } else {
+            *outProbability = bigramEntry.getProbability();
+        }
+    }
+    if (outHasNext) {
+        *outHasNext = bigramEntry.hasNext();
+    }
+}
+
+bool Ver4BigramListPolicy::addNewEntry(const int terminalId, const int newTargetTerminalId,
+        const BigramProperty *const bigramProperty, bool *const outAddedNewEntry) {
+    // 1. The word has no bigrams yet.
+    // 2. The word has bigrams, and there is the target in the list.
+    // 3. The word has bigrams, and there is an invalid entry that can be reclaimed.
+    // 4. The word has bigrams. We have to append new bigram entry to the list.
+    // 5. Same as 4, but the list is the last entry of the content file.
+    if (outAddedNewEntry) {
+        *outAddedNewEntry = false;
+    }
+    const int bigramListPos = mBigramDictContent->getBigramListHeadPos(terminalId);
+    if (bigramListPos == NOT_A_DICT_POS) {
+        // Case 1. PtNode that doesn't have a bigram list.
+        // Create new bigram list.
+        if (!mBigramDictContent->createNewBigramList(terminalId)) {
+            return false;
+        }
+        const BigramEntry newBigramEntry(false /* hasNext */, NOT_A_PROBABILITY,
+                newTargetTerminalId);
+        const BigramEntry bigramEntryToWrite = createUpdatedBigramEntryFrom(&newBigramEntry,
+                bigramProperty);
+        // Write an entry.
+        const int writingPos =  mBigramDictContent->getBigramListHeadPos(terminalId);
+        if (!mBigramDictContent->writeBigramEntry(&bigramEntryToWrite, writingPos)) {
+            return false;
+        }
+        if (outAddedNewEntry) {
+            *outAddedNewEntry = true;
+        }
+        return true;
+    }
+
+    int tailEntryPos = NOT_A_DICT_POS;
+    const int entryPosToUpdate = getEntryPosToUpdate(newTargetTerminalId, bigramListPos,
+            &tailEntryPos);
+    if (tailEntryPos != NOT_A_DICT_POS || entryPosToUpdate == NOT_A_DICT_POS) {
+        // Case 4, 5.
+        // Add new entry to the bigram list.
+        if (tailEntryPos == NOT_A_DICT_POS) {
+            // Case 4. Create new bigram list.
+            if (!mBigramDictContent->createNewBigramList(terminalId)) {
+                return false;
+            }
+            const int destPos = mBigramDictContent->getBigramListHeadPos(terminalId);
+            // Copy existing bigram list.
+            if (!mBigramDictContent->copyBigramList(bigramListPos, destPos, &tailEntryPos)) {
+                return false;
+            }
+        }
+        // Write new entry at the tail position of the bigram content.
+        const BigramEntry newBigramEntry(false /* hasNext */, NOT_A_PROBABILITY,
+                newTargetTerminalId);
+        const BigramEntry bigramEntryToWrite = createUpdatedBigramEntryFrom(
+                &newBigramEntry, bigramProperty);
+        if (!mBigramDictContent->writeBigramEntryAtTail(&bigramEntryToWrite)) {
+            return false;
+        }
+        // Update has next flag of the tail entry.
+        if (!updateHasNextFlag(true /* hasNext */, tailEntryPos)) {
+            return false;
+        }
+        if (outAddedNewEntry) {
+            *outAddedNewEntry = true;
+        }
+        return true;
+    }
+
+    // Case 2. Overwrite the existing entry. Case 3. Reclaim and reuse the existing invalid entry.
+    const BigramEntry originalBigramEntry = mBigramDictContent->getBigramEntry(entryPosToUpdate);
+    if (!originalBigramEntry.isValid()) {
+        // Case 3. Reuse the existing invalid entry. outAddedNewEntry is false when an existing
+        // entry is updated.
+        if (outAddedNewEntry) {
+            *outAddedNewEntry = true;
+        }
+    }
+    const BigramEntry updatedBigramEntry =
+            originalBigramEntry.updateTargetTerminalIdAndGetEntry(newTargetTerminalId);
+    const BigramEntry bigramEntryToWrite = createUpdatedBigramEntryFrom(
+            &updatedBigramEntry, bigramProperty);
+    return mBigramDictContent->writeBigramEntry(&bigramEntryToWrite, entryPosToUpdate);
+}
+
+bool Ver4BigramListPolicy::removeEntry(const int terminalId, const int targetTerminalId) {
+    const int bigramListPos = mBigramDictContent->getBigramListHeadPos(terminalId);
+    if (bigramListPos == NOT_A_DICT_POS) {
+        // Bigram list doesn't exist.
+        return false;
+    }
+    const int entryPosToUpdate = getEntryPosToUpdate(targetTerminalId, bigramListPos,
+            nullptr /* outTailEntryPos */);
+    if (entryPosToUpdate == NOT_A_DICT_POS) {
+        // Bigram entry doesn't exist.
+        return false;
+    }
+    const BigramEntry bigramEntry = mBigramDictContent->getBigramEntry(entryPosToUpdate);
+    if (targetTerminalId != bigramEntry.getTargetTerminalId()) {
+        // Bigram entry doesn't exist.
+        return false;
+    }
+    // Remove bigram entry by marking it as invalid entry and overwriting the original entry.
+    const BigramEntry updatedBigramEntry = bigramEntry.getInvalidatedEntry();
+    return mBigramDictContent->writeBigramEntry(&updatedBigramEntry, entryPosToUpdate);
+}
+
+bool Ver4BigramListPolicy::updateAllBigramEntriesAndDeleteUselessEntries(const int terminalId,
+        int *const outBigramCount) {
+    const int bigramListPos = mBigramDictContent->getBigramListHeadPos(terminalId);
+    if (bigramListPos == NOT_A_DICT_POS) {
+        // Bigram list doesn't exist.
+        return true;
+    }
+    bool hasNext = true;
+    int readingPos = bigramListPos;
+    while (hasNext) {
+        const int entryPos = readingPos;
+        const BigramEntry bigramEntry =
+                mBigramDictContent->getBigramEntryAndAdvancePosition(&readingPos);
+        hasNext = bigramEntry.hasNext();
+        if (!bigramEntry.isValid()) {
+            continue;
+        }
+        const int targetPtNodePos = mTerminalPositionLookupTable->getTerminalPtNodePosition(
+                bigramEntry.getTargetTerminalId());
+        if (targetPtNodePos == NOT_A_DICT_POS) {
+            // Invalidate bigram entry.
+            const BigramEntry updatedBigramEntry = bigramEntry.getInvalidatedEntry();
+            if (!mBigramDictContent->writeBigramEntry(&updatedBigramEntry, entryPos)) {
+                return false;
+            }
+        } else if (bigramEntry.hasHistoricalInfo()) {
+            const HistoricalInfo historicalInfo = ForgettingCurveUtils::createHistoricalInfoToSave(
+                    bigramEntry.getHistoricalInfo(), mHeaderPolicy);
+            if (ForgettingCurveUtils::needsToKeep(&historicalInfo, mHeaderPolicy)) {
+                const BigramEntry updatedBigramEntry =
+                        bigramEntry.updateHistoricalInfoAndGetEntry(&historicalInfo);
+                if (!mBigramDictContent->writeBigramEntry(&updatedBigramEntry, entryPos)) {
+                    return false;
+                }
+                *outBigramCount += 1;
+            } else {
+                // Remove entry.
+                const BigramEntry updatedBigramEntry = bigramEntry.getInvalidatedEntry();
+                if (!mBigramDictContent->writeBigramEntry(&updatedBigramEntry, entryPos)) {
+                    return false;
+                }
+            }
+        } else {
+            *outBigramCount += 1;
+        }
+    }
+    return true;
+}
+
+int Ver4BigramListPolicy::getBigramEntryConut(const int terminalId) {
+    const int bigramListPos = mBigramDictContent->getBigramListHeadPos(terminalId);
+    if (bigramListPos == NOT_A_DICT_POS) {
+        // Bigram list doesn't exist.
+        return 0;
+    }
+    int bigramCount = 0;
+    bool hasNext = true;
+    int readingPos = bigramListPos;
+    while (hasNext) {
+        const BigramEntry bigramEntry =
+                mBigramDictContent->getBigramEntryAndAdvancePosition(&readingPos);
+        hasNext = bigramEntry.hasNext();
+        if (bigramEntry.isValid()) {
+            bigramCount++;
+        }
+    }
+    return bigramCount;
+}
+
+int Ver4BigramListPolicy::getEntryPosToUpdate(const int targetTerminalIdToFind,
+        const int bigramListPos, int *const outTailEntryPos) const {
+    if (outTailEntryPos) {
+        *outTailEntryPos = NOT_A_DICT_POS;
+    }
+    bool hasNext = true;
+    int invalidEntryPos = NOT_A_DICT_POS;
+    int readingPos = bigramListPos;
+    while (hasNext) {
+        const int entryPos = readingPos;
+        const BigramEntry bigramEntry =
+                mBigramDictContent->getBigramEntryAndAdvancePosition(&readingPos);
+        hasNext = bigramEntry.hasNext();
+        if (bigramEntry.getTargetTerminalId() == targetTerminalIdToFind) {
+            // Entry with same target is found.
+            return entryPos;
+        } else if (!bigramEntry.isValid()) {
+            // Invalid entry that can be reused is found.
+            invalidEntryPos = entryPos;
+        }
+        if (!hasNext && mBigramDictContent->isContentTailPos(readingPos)) {
+            if (outTailEntryPos) {
+                *outTailEntryPos = entryPos;
+            }
+        }
+    }
+    return invalidEntryPos;
+}
+
+const BigramEntry Ver4BigramListPolicy::createUpdatedBigramEntryFrom(
+        const BigramEntry *const originalBigramEntry,
+        const BigramProperty *const bigramProperty) const {
+    // TODO: Consolidate historical info and probability.
+    if (mHeaderPolicy->hasHistoricalInfoOfWords()) {
+        const HistoricalInfo historicalInfoForUpdate(bigramProperty->getTimestamp(),
+                bigramProperty->getLevel(), bigramProperty->getCount());
+        const HistoricalInfo updatedHistoricalInfo =
+                ForgettingCurveUtils::createUpdatedHistoricalInfo(
+                        originalBigramEntry->getHistoricalInfo(), bigramProperty->getProbability(),
+                        &historicalInfoForUpdate, mHeaderPolicy);
+        return originalBigramEntry->updateHistoricalInfoAndGetEntry(&updatedHistoricalInfo);
+    } else {
+        return originalBigramEntry->updateProbabilityAndGetEntry(bigramProperty->getProbability());
+    }
+}
+
+bool Ver4BigramListPolicy::updateHasNextFlag(const bool hasNext, const int bigramEntryPos) {
+    const BigramEntry bigramEntry = mBigramDictContent->getBigramEntry(bigramEntryPos);
+    const BigramEntry updatedBigramEntry = bigramEntry.updateHasNextAndGetEntry(hasNext);
+    return mBigramDictContent->writeBigramEntry(&updatedBigramEntry, bigramEntryPos);
+}
+
+} // namespace v401
+} // namespace backward
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/bigram/ver4_bigram_list_policy.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/bigram/ver4_bigram_list_policy.h
new file mode 100644
index 0000000..adf687b
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/bigram/ver4_bigram_list_policy.h
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT CHANGE THE LOGIC IN THIS FILE !!!!!
+ * Do not edit this file other than updating policy's interface.
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/bigram/ver4_bigram_list_policy.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_VER4_BIGRAM_LIST_POLICY_H
+#define LATINIME_BACKWARD_V401_VER4_BIGRAM_LIST_POLICY_H
+
+#include "defines.h"
+#include "suggest/core/policy/dictionary_bigrams_structure_policy.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/bigram_entry.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+class BigramDictContent;
+} // namespace v401
+} // namespace backward
+class BigramProperty;
+namespace backward {
+namespace v401 {
+} // namespace v401
+} // namespace backward
+class HeaderPolicy;
+namespace backward {
+namespace v401 {
+class TerminalPositionLookupTable;
+
+class Ver4BigramListPolicy : public DictionaryBigramsStructurePolicy {
+ public:
+    Ver4BigramListPolicy(BigramDictContent *const bigramDictContent,
+            const TerminalPositionLookupTable *const terminalPositionLookupTable,
+            const HeaderPolicy *const headerPolicy)
+            : mBigramDictContent(bigramDictContent),
+              mTerminalPositionLookupTable(terminalPositionLookupTable),
+              mHeaderPolicy(headerPolicy) {}
+
+    void getNextBigram(int *const outBigramPos, int *const outProbability,
+            bool *const outHasNext, int *const bigramEntryPos) const;
+
+    void skipAllBigrams(int *const pos) const {
+        // Do nothing because we don't need to skip bigram lists in ver4 dictionaries.
+    }
+
+    bool addNewEntry(const int terminalId, const int newTargetTerminalId,
+            const BigramProperty *const bigramProperty, bool *const outAddedNewEntry);
+
+    bool removeEntry(const int terminalId, const int targetTerminalId);
+
+    bool updateAllBigramEntriesAndDeleteUselessEntries(const int terminalId,
+            int *const outBigramCount);
+
+    int getBigramEntryConut(const int terminalId);
+
+ private:
+    DISALLOW_IMPLICIT_CONSTRUCTORS(Ver4BigramListPolicy);
+
+    int getEntryPosToUpdate(const int targetTerminalIdToFind, const int bigramListPos,
+            int *const outTailEntryPos) const;
+
+    const BigramEntry createUpdatedBigramEntryFrom(const BigramEntry *const originalBigramEntry,
+            const BigramProperty *const bigramProperty) const;
+
+    bool updateHasNextFlag(const bool hasNext, const int bigramEntryPos);
+
+    BigramDictContent *const mBigramDictContent;
+    const TerminalPositionLookupTable *const mTerminalPositionLookupTable;
+    const HeaderPolicy *const mHeaderPolicy;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_VER4_BIGRAM_LIST_POLICY_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/bigram_dict_content.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/bigram_dict_content.cpp
new file mode 100644
index 0000000..1e53ff9
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/bigram_dict_content.cpp
@@ -0,0 +1,224 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/content/bigram_dict_content.cpp
+ */
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/bigram_dict_content.h"
+
+#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+const BigramEntry BigramDictContent::getBigramEntryAndAdvancePosition(
+        int *const bigramEntryPos) const {
+    const BufferWithExtendableBuffer *const bigramListBuffer = getContentBuffer();
+    if (*bigramEntryPos < 0 || *bigramEntryPos >=  bigramListBuffer->getTailPosition()) {
+        AKLOGE("Invalid bigram entry position. bigramEntryPos: %d, bufSize: %d",
+                *bigramEntryPos, bigramListBuffer->getTailPosition());
+        ASSERT(false);
+        return BigramEntry(false /* hasNext */, NOT_A_PROBABILITY,
+                Ver4DictConstants::NOT_A_TERMINAL_ID);
+    }
+    const int bigramFlags = bigramListBuffer->readUintAndAdvancePosition(
+            Ver4DictConstants::BIGRAM_FLAGS_FIELD_SIZE, bigramEntryPos);
+    const bool hasNext = (bigramFlags & Ver4DictConstants::BIGRAM_HAS_NEXT_MASK) != 0;
+    int probability = NOT_A_PROBABILITY;
+    int timestamp = NOT_A_TIMESTAMP;
+    int level = 0;
+    int count = 0;
+    if (mHasHistoricalInfo) {
+        probability = bigramListBuffer->readUintAndAdvancePosition(
+                Ver4DictConstants::PROBABILITY_SIZE, bigramEntryPos);
+        timestamp = bigramListBuffer->readUintAndAdvancePosition(
+                Ver4DictConstants::TIME_STAMP_FIELD_SIZE, bigramEntryPos);
+        level = bigramListBuffer->readUintAndAdvancePosition(
+                Ver4DictConstants::WORD_LEVEL_FIELD_SIZE, bigramEntryPos);
+        count = bigramListBuffer->readUintAndAdvancePosition(
+                Ver4DictConstants::WORD_COUNT_FIELD_SIZE, bigramEntryPos);
+    } else {
+        probability = bigramFlags & Ver4DictConstants::BIGRAM_PROBABILITY_MASK;
+    }
+    const int encodedTargetTerminalId = bigramListBuffer->readUintAndAdvancePosition(
+            Ver4DictConstants::BIGRAM_TARGET_TERMINAL_ID_FIELD_SIZE, bigramEntryPos);
+    const int targetTerminalId =
+            (encodedTargetTerminalId == Ver4DictConstants::INVALID_BIGRAM_TARGET_TERMINAL_ID) ?
+                    Ver4DictConstants::NOT_A_TERMINAL_ID : encodedTargetTerminalId;
+    if (mHasHistoricalInfo) {
+        const HistoricalInfo historicalInfo(timestamp, level, count);
+        return BigramEntry(hasNext, probability, &historicalInfo, targetTerminalId);
+    } else {
+        return BigramEntry(hasNext, probability, targetTerminalId);
+    }
+}
+
+bool BigramDictContent::writeBigramEntryAndAdvancePosition(
+        const BigramEntry *const bigramEntryToWrite, int *const entryWritingPos) {
+    BufferWithExtendableBuffer *const bigramListBuffer = getWritableContentBuffer();
+    const int bigramFlags = createAndGetBigramFlags(
+            mHasHistoricalInfo ? 0 : bigramEntryToWrite->getProbability(),
+            bigramEntryToWrite->hasNext());
+    if (!bigramListBuffer->writeUintAndAdvancePosition(bigramFlags,
+            Ver4DictConstants::BIGRAM_FLAGS_FIELD_SIZE, entryWritingPos)) {
+        AKLOGE("Cannot write bigram flags. pos: %d, flags: %x", *entryWritingPos, bigramFlags);
+        return false;
+    }
+    if (mHasHistoricalInfo) {
+        if (!bigramListBuffer->writeUintAndAdvancePosition(bigramEntryToWrite->getProbability(),
+                Ver4DictConstants::PROBABILITY_SIZE, entryWritingPos)) {
+            AKLOGE("Cannot write bigram probability. pos: %d, probability: %d", *entryWritingPos,
+                    bigramEntryToWrite->getProbability());
+            return false;
+        }
+        const HistoricalInfo *const historicalInfo = bigramEntryToWrite->getHistoricalInfo();
+        if (!bigramListBuffer->writeUintAndAdvancePosition(historicalInfo->getTimeStamp(),
+                Ver4DictConstants::TIME_STAMP_FIELD_SIZE, entryWritingPos)) {
+            AKLOGE("Cannot write bigram timestamps. pos: %d, timestamp: %d", *entryWritingPos,
+                    historicalInfo->getTimeStamp());
+            return false;
+        }
+        if (!bigramListBuffer->writeUintAndAdvancePosition(historicalInfo->getLevel(),
+                Ver4DictConstants::WORD_LEVEL_FIELD_SIZE, entryWritingPos)) {
+            AKLOGE("Cannot write bigram level. pos: %d, level: %d", *entryWritingPos,
+                    historicalInfo->getLevel());
+            return false;
+        }
+        if (!bigramListBuffer->writeUintAndAdvancePosition(historicalInfo->getCount(),
+                Ver4DictConstants::WORD_COUNT_FIELD_SIZE, entryWritingPos)) {
+            AKLOGE("Cannot write bigram count. pos: %d, count: %d", *entryWritingPos,
+                    historicalInfo->getCount());
+            return false;
+        }
+    }
+    const int targetTerminalIdToWrite =
+            (bigramEntryToWrite->getTargetTerminalId() == Ver4DictConstants::NOT_A_TERMINAL_ID) ?
+                    Ver4DictConstants::INVALID_BIGRAM_TARGET_TERMINAL_ID :
+                            bigramEntryToWrite->getTargetTerminalId();
+    if (!bigramListBuffer->writeUintAndAdvancePosition(targetTerminalIdToWrite,
+            Ver4DictConstants::BIGRAM_TARGET_TERMINAL_ID_FIELD_SIZE, entryWritingPos)) {
+        AKLOGE("Cannot write bigram target terminal id. pos: %d, target terminal id: %d",
+                *entryWritingPos, bigramEntryToWrite->getTargetTerminalId());
+        return false;
+    }
+    return true;
+}
+
+bool BigramDictContent::copyBigramList(const int bigramListPos, const int toPos,
+        int *const outTailEntryPos) {
+    int readingPos = bigramListPos;
+    int writingPos = toPos;
+    bool hasNext = true;
+    while (hasNext) {
+        const BigramEntry bigramEntry = getBigramEntryAndAdvancePosition(&readingPos);
+        hasNext = bigramEntry.hasNext();
+        if (!hasNext) {
+            *outTailEntryPos = writingPos;
+        }
+        if (!writeBigramEntryAndAdvancePosition(&bigramEntry, &writingPos)) {
+            AKLOGE("Cannot write bigram entry to copy. pos: %d", writingPos);
+            return false;
+        }
+    }
+    return true;
+}
+
+bool BigramDictContent::runGC(const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
+        const BigramDictContent *const originalBigramDictContent,
+        int *const outBigramEntryCount) {
+    for (TerminalPositionLookupTable::TerminalIdMap::const_iterator it = terminalIdMap->begin();
+            it != terminalIdMap->end(); ++it) {
+        const int originalBigramListPos =
+                originalBigramDictContent->getBigramListHeadPos(it->first);
+        if (originalBigramListPos == NOT_A_DICT_POS) {
+            // This terminal does not have a bigram list.
+            continue;
+        }
+        const int bigramListPos = getContentBuffer()->getTailPosition();
+        int bigramEntryCount = 0;
+        // Copy bigram list with GC from original content.
+        if (!runGCBigramList(originalBigramListPos, originalBigramDictContent, bigramListPos,
+                terminalIdMap, &bigramEntryCount)) {
+            AKLOGE("Cannot complete GC for the bigram list. original pos: %d, pos: %d",
+                    originalBigramListPos, bigramListPos);
+            return false;
+        }
+        if (bigramEntryCount == 0) {
+            // All bigram entries are useless. This terminal does not have a bigram list.
+            continue;
+        }
+        *outBigramEntryCount += bigramEntryCount;
+        // Set bigram list position to the lookup table.
+        if (!getUpdatableAddressLookupTable()->set(it->second, bigramListPos)) {
+            AKLOGE("Cannot set bigram list position. terminal id: %d, pos: %d",
+                    it->second, bigramListPos);
+            return false;
+        }
+    }
+    return true;
+}
+
+// Returns whether GC for the bigram list was succeeded or not.
+bool BigramDictContent::runGCBigramList(const int bigramListPos,
+        const BigramDictContent *const sourceBigramDictContent, const int toPos,
+        const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
+        int *const outEntrycount) {
+    bool hasNext = true;
+    int readingPos = bigramListPos;
+    int writingPos = toPos;
+    int lastEntryPos = NOT_A_DICT_POS;
+    while (hasNext) {
+        const BigramEntry originalBigramEntry =
+                sourceBigramDictContent->getBigramEntryAndAdvancePosition(&readingPos);
+        hasNext = originalBigramEntry.hasNext();
+        if (originalBigramEntry.getTargetTerminalId() == Ver4DictConstants::NOT_A_TERMINAL_ID) {
+            continue;
+        }
+        TerminalPositionLookupTable::TerminalIdMap::const_iterator it =
+                terminalIdMap->find(originalBigramEntry.getTargetTerminalId());
+        if (it == terminalIdMap->end()) {
+            // Target word has been removed.
+            continue;
+        }
+        lastEntryPos = hasNext ? writingPos : NOT_A_DICT_POS;
+        const BigramEntry updatedBigramEntry =
+                originalBigramEntry.updateTargetTerminalIdAndGetEntry(it->second);
+        if (!writeBigramEntryAndAdvancePosition(&updatedBigramEntry, &writingPos)) {
+            AKLOGE("Cannot write bigram entry to run GC. pos: %d", writingPos);
+            return false;
+        }
+        *outEntrycount += 1;
+    }
+    if (lastEntryPos != NOT_A_DICT_POS) {
+        // Update has next flag in the last written entry.
+        const BigramEntry bigramEntry = getBigramEntry(lastEntryPos).updateHasNextAndGetEntry(
+                false /* hasNext */);
+        if (!writeBigramEntry(&bigramEntry, lastEntryPos)) {
+            AKLOGE("Cannot write bigram entry to set hasNext flag after GC. pos: %d", writingPos);
+            return false;
+        }
+    }
+    return true;
+}
+
+} // namespace v401
+} // namespace backward
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/bigram_dict_content.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/bigram_dict_content.h
new file mode 100644
index 0000000..f9c474b
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/bigram_dict_content.h
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/content/bigram_dict_content.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_BIGRAM_DICT_CONTENT_H
+#define LATINIME_BACKWARD_V401_BIGRAM_DICT_CONTENT_H
+
+#include "defines.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/bigram_entry.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/sparse_table_dict_content.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+class BigramDictContent : public SparseTableDictContent {
+ public:
+    BigramDictContent(const char *const dictPath, const bool hasHistoricalInfo,
+            const bool isUpdatable)
+            : SparseTableDictContent(dictPath,
+                      Ver4DictConstants::BIGRAM_LOOKUP_TABLE_FILE_EXTENSION,
+                      Ver4DictConstants::BIGRAM_CONTENT_TABLE_FILE_EXTENSION,
+                      Ver4DictConstants::BIGRAM_FILE_EXTENSION, isUpdatable,
+                      Ver4DictConstants::BIGRAM_ADDRESS_TABLE_BLOCK_SIZE,
+                      Ver4DictConstants::BIGRAM_ADDRESS_TABLE_DATA_SIZE),
+              mHasHistoricalInfo(hasHistoricalInfo) {}
+
+    BigramDictContent(const bool hasHistoricalInfo)
+            : SparseTableDictContent(Ver4DictConstants::BIGRAM_ADDRESS_TABLE_BLOCK_SIZE,
+                      Ver4DictConstants::BIGRAM_ADDRESS_TABLE_DATA_SIZE),
+              mHasHistoricalInfo(hasHistoricalInfo) {}
+
+    const BigramEntry getBigramEntry(const int bigramEntryPos) const {
+        int readingPos = bigramEntryPos;
+        return getBigramEntryAndAdvancePosition(&readingPos);
+    }
+
+    const BigramEntry getBigramEntryAndAdvancePosition(int *const bigramEntryPos) const;
+
+    // Returns head position of bigram list for a PtNode specified by terminalId.
+    int getBigramListHeadPos(const int terminalId) const {
+        const SparseTable *const addressLookupTable = getAddressLookupTable();
+        if (!addressLookupTable->contains(terminalId)) {
+            return NOT_A_DICT_POS;
+        }
+        return addressLookupTable->get(terminalId);
+    }
+
+    bool writeBigramEntryAtTail(const BigramEntry *const bigramEntryToWrite) {
+        int writingPos = getContentBuffer()->getTailPosition();
+        return writeBigramEntryAndAdvancePosition(bigramEntryToWrite, &writingPos);
+    }
+
+    bool writeBigramEntry(const BigramEntry *const bigramEntryToWrite, const int entryWritingPos) {
+        int writingPos = entryWritingPos;
+        return writeBigramEntryAndAdvancePosition(bigramEntryToWrite, &writingPos);
+    }
+
+    bool writeBigramEntryAndAdvancePosition(const BigramEntry *const bigramEntryToWrite,
+            int *const entryWritingPos);
+
+    bool createNewBigramList(const int terminalId) {
+        const int bigramListPos = getContentBuffer()->getTailPosition();
+        return getUpdatableAddressLookupTable()->set(terminalId, bigramListPos);
+    }
+
+    bool copyBigramList(const int bigramListPos, const int toPos, int *const outTailEntryPos);
+
+    bool flushToFile(const char *const dictPath) const {
+        return flush(dictPath, Ver4DictConstants::BIGRAM_LOOKUP_TABLE_FILE_EXTENSION,
+                Ver4DictConstants::BIGRAM_CONTENT_TABLE_FILE_EXTENSION,
+                Ver4DictConstants::BIGRAM_FILE_EXTENSION);
+    }
+
+    bool runGC(const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
+            const BigramDictContent *const originalBigramDictContent,
+            int *const outBigramEntryCount);
+
+    bool isContentTailPos(const int pos) const {
+        return pos == getContentBuffer()->getTailPosition();
+    }
+
+ private:
+    DISALLOW_COPY_AND_ASSIGN(BigramDictContent);
+
+    int createAndGetBigramFlags(const int probability, const bool hasNext) const {
+        return (probability & Ver4DictConstants::BIGRAM_PROBABILITY_MASK)
+                | (hasNext ? Ver4DictConstants::BIGRAM_HAS_NEXT_MASK : 0);
+    }
+
+    bool runGCBigramList(const int bigramListPos,
+            const BigramDictContent *const sourceBigramDictContent, const int toPos,
+            const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
+            int *const outEntryCount);
+
+    bool mHasHistoricalInfo;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_BIGRAM_DICT_CONTENT_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/bigram_entry.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/bigram_entry.h
new file mode 100644
index 0000000..82c4b53
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/bigram_entry.h
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/content/bigram_entry.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_BIGRAM_ENTRY_H
+#define LATINIME_BACKWARD_V401_BIGRAM_ENTRY_H
+
+#include "defines.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h"
+#include "suggest/policyimpl/dictionary/utils/historical_info.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+class BigramEntry {
+ public:
+    BigramEntry(const BigramEntry& bigramEntry)
+            : mHasNext(bigramEntry.mHasNext), mProbability(bigramEntry.mProbability),
+              mHistoricalInfo(), mTargetTerminalId(bigramEntry.mTargetTerminalId) {}
+
+    // Entry with historical information.
+    BigramEntry(const bool hasNext, const int probability, const int targetTerminalId)
+            : mHasNext(hasNext), mProbability(probability), mHistoricalInfo(),
+              mTargetTerminalId(targetTerminalId) {}
+
+    // Entry with historical information.
+    BigramEntry(const bool hasNext, const int probability,
+            const HistoricalInfo *const historicalInfo, const int targetTerminalId)
+            : mHasNext(hasNext), mProbability(probability), mHistoricalInfo(*historicalInfo),
+              mTargetTerminalId(targetTerminalId) {}
+
+    const BigramEntry getInvalidatedEntry() const {
+        return updateTargetTerminalIdAndGetEntry(Ver4DictConstants::NOT_A_TERMINAL_ID);
+    }
+
+    const BigramEntry updateHasNextAndGetEntry(const bool hasNext) const {
+        return BigramEntry(hasNext, mProbability, &mHistoricalInfo, mTargetTerminalId);
+    }
+
+    const BigramEntry updateTargetTerminalIdAndGetEntry(const int newTargetTerminalId) const {
+        return BigramEntry(mHasNext, mProbability, &mHistoricalInfo, newTargetTerminalId);
+    }
+
+    const BigramEntry updateProbabilityAndGetEntry(const int probability) const {
+        return BigramEntry(mHasNext, probability, &mHistoricalInfo, mTargetTerminalId);
+    }
+
+    const BigramEntry updateHistoricalInfoAndGetEntry(
+            const HistoricalInfo *const historicalInfo) const {
+        return BigramEntry(mHasNext, mProbability, historicalInfo, mTargetTerminalId);
+    }
+
+    bool isValid() const {
+        return mTargetTerminalId != Ver4DictConstants::NOT_A_TERMINAL_ID;
+    }
+
+    bool hasNext() const {
+        return mHasNext;
+    }
+
+    int getProbability() const {
+        return mProbability;
+    }
+
+    bool hasHistoricalInfo() const {
+        return mHistoricalInfo.isValid();
+    }
+
+    const HistoricalInfo *getHistoricalInfo() const {
+        return &mHistoricalInfo;
+    }
+
+    int getTargetTerminalId() const {
+        return mTargetTerminalId;
+    }
+
+ private:
+    // Copy constructor is public to use this class as a type of return value.
+    DISALLOW_DEFAULT_CONSTRUCTOR(BigramEntry);
+    DISALLOW_ASSIGNMENT_OPERATOR(BigramEntry);
+
+    const bool mHasNext;
+    const int mProbability;
+    const HistoricalInfo mHistoricalInfo;
+    const int mTargetTerminalId;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_BIGRAM_ENTRY_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/dict_content.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/dict_content.h
new file mode 100644
index 0000000..39e2900
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/dict_content.h
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/content/dict_content.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_DICT_CONTENT_H
+#define LATINIME_BACKWARD_V401_DICT_CONTENT_H
+
+#include "defines.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+class DictContent {
+ public:
+    virtual ~DictContent() {}
+    virtual bool isValid() const = 0;
+
+ protected:
+    DictContent() {}
+
+ private:
+    DISALLOW_COPY_AND_ASSIGN(DictContent);
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_DICT_CONTENT_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/probability_dict_content.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/probability_dict_content.cpp
new file mode 100644
index 0000000..337b97c
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/probability_dict_content.cpp
@@ -0,0 +1,171 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/content/probability_dict_content.cpp
+ */
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/probability_dict_content.h"
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/probability_entry.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h"
+#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+const ProbabilityEntry ProbabilityDictContent::getProbabilityEntry(const int terminalId) const {
+    if (terminalId < 0 || terminalId >= mSize) {
+        // This method can be called with invalid terminal id during GC.
+        return ProbabilityEntry(0 /* flags */, NOT_A_PROBABILITY);
+    }
+    const BufferWithExtendableBuffer *const buffer = getBuffer();
+    int entryPos = getEntryPos(terminalId);
+    const int flags = buffer->readUintAndAdvancePosition(
+            Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE, &entryPos);
+    const int probability = buffer->readUintAndAdvancePosition(
+            Ver4DictConstants::PROBABILITY_SIZE, &entryPos);
+    if (mHasHistoricalInfo) {
+        const int timestamp = buffer->readUintAndAdvancePosition(
+                Ver4DictConstants::TIME_STAMP_FIELD_SIZE, &entryPos);
+        const int level = buffer->readUintAndAdvancePosition(
+                Ver4DictConstants::WORD_LEVEL_FIELD_SIZE, &entryPos);
+        const int count = buffer->readUintAndAdvancePosition(
+                Ver4DictConstants::WORD_COUNT_FIELD_SIZE, &entryPos);
+        const HistoricalInfo historicalInfo(timestamp, level, count);
+        return ProbabilityEntry(flags, probability, &historicalInfo);
+    } else {
+        return ProbabilityEntry(flags, probability);
+    }
+}
+
+bool ProbabilityDictContent::setProbabilityEntry(const int terminalId,
+        const ProbabilityEntry *const probabilityEntry) {
+    if (terminalId < 0) {
+        return false;
+    }
+    const int entryPos = getEntryPos(terminalId);
+    if (terminalId >= mSize) {
+        ProbabilityEntry dummyEntry;
+        // Write new entry.
+        int writingPos = getBuffer()->getTailPosition();
+        while (writingPos <= entryPos) {
+            // Fulfilling with dummy entries until writingPos.
+            if (!writeEntry(&dummyEntry, writingPos)) {
+                AKLOGE("Cannot write dummy entry. pos: %d, mSize: %d", writingPos, mSize);
+                return false;
+            }
+            writingPos += getEntrySize();
+            mSize++;
+        }
+    }
+    return writeEntry(probabilityEntry, entryPos);
+}
+
+bool ProbabilityDictContent::flushToFile(const char *const dictPath) const {
+    if (getEntryPos(mSize) < getBuffer()->getTailPosition()) {
+        ProbabilityDictContent probabilityDictContentToWrite(mHasHistoricalInfo);
+        for (int i = 0; i < mSize; ++i) {
+            const ProbabilityEntry probabilityEntry = getProbabilityEntry(i);
+            if (!probabilityDictContentToWrite.setProbabilityEntry(i, &probabilityEntry)) {
+                AKLOGE("Cannot set probability entry in flushToFile. terminalId: %d", i);
+                return false;
+            }
+        }
+        return probabilityDictContentToWrite.flush(dictPath,
+                Ver4DictConstants::FREQ_FILE_EXTENSION);
+    } else {
+        return flush(dictPath, Ver4DictConstants::FREQ_FILE_EXTENSION);
+    }
+}
+
+bool ProbabilityDictContent::runGC(
+        const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
+        const ProbabilityDictContent *const originalProbabilityDictContent) {
+    mSize = 0;
+    for (TerminalPositionLookupTable::TerminalIdMap::const_iterator it = terminalIdMap->begin();
+            it != terminalIdMap->end(); ++it) {
+        const ProbabilityEntry probabilityEntry =
+                originalProbabilityDictContent->getProbabilityEntry(it->first);
+        if (!setProbabilityEntry(it->second, &probabilityEntry)) {
+            AKLOGE("Cannot set probability entry in runGC. terminalId: %d", it->second);
+            return false;
+        }
+        mSize++;
+    }
+    return true;
+}
+
+int ProbabilityDictContent::getEntrySize() const {
+    if (mHasHistoricalInfo) {
+        return Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE
+                + Ver4DictConstants::PROBABILITY_SIZE
+                + Ver4DictConstants::TIME_STAMP_FIELD_SIZE
+                + Ver4DictConstants::WORD_LEVEL_FIELD_SIZE
+                + Ver4DictConstants::WORD_COUNT_FIELD_SIZE;
+    } else {
+        return Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE
+                + Ver4DictConstants::PROBABILITY_SIZE;
+    }
+}
+
+int ProbabilityDictContent::getEntryPos(const int terminalId) const {
+    return terminalId * getEntrySize();
+}
+
+bool ProbabilityDictContent::writeEntry(const ProbabilityEntry *const probabilityEntry,
+        const int entryPos) {
+    BufferWithExtendableBuffer *const bufferToWrite = getWritableBuffer();
+    int writingPos = entryPos;
+    if (!bufferToWrite->writeUintAndAdvancePosition(probabilityEntry->getFlags(),
+            Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE, &writingPos)) {
+        AKLOGE("Cannot write flags in probability dict content. pos: %d", writingPos);
+        return false;
+    }
+    if (!bufferToWrite->writeUintAndAdvancePosition(probabilityEntry->getProbability(),
+            Ver4DictConstants::PROBABILITY_SIZE, &writingPos)) {
+        AKLOGE("Cannot write probability in probability dict content. pos: %d", writingPos);
+        return false;
+    }
+    if (mHasHistoricalInfo) {
+        const HistoricalInfo *const historicalInfo = probabilityEntry->getHistoricalInfo();
+        if (!bufferToWrite->writeUintAndAdvancePosition(historicalInfo->getTimeStamp(),
+                Ver4DictConstants::TIME_STAMP_FIELD_SIZE, &writingPos)) {
+            AKLOGE("Cannot write timestamp in probability dict content. pos: %d", writingPos);
+            return false;
+        }
+        if (!bufferToWrite->writeUintAndAdvancePosition(historicalInfo->getLevel(),
+                Ver4DictConstants::WORD_LEVEL_FIELD_SIZE, &writingPos)) {
+            AKLOGE("Cannot write level in probability dict content. pos: %d", writingPos);
+            return false;
+        }
+        if (!bufferToWrite->writeUintAndAdvancePosition(historicalInfo->getCount(),
+                Ver4DictConstants::WORD_COUNT_FIELD_SIZE, &writingPos)) {
+            AKLOGE("Cannot write count in probability dict content. pos: %d", writingPos);
+            return false;
+        }
+    }
+    return true;
+}
+
+} // namespace v401
+} // namespace backward
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/probability_dict_content.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/probability_dict_content.h
new file mode 100644
index 0000000..db30709
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/probability_dict_content.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/content/probability_dict_content.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_PROBABILITY_DICT_CONTENT_H
+#define LATINIME_BACKWARD_V401_PROBABILITY_DICT_CONTENT_H
+
+#include "defines.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/single_dict_content.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h"
+#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+class ProbabilityEntry;
+
+class ProbabilityDictContent : public SingleDictContent {
+ public:
+    ProbabilityDictContent(const char *const dictPath, const bool hasHistoricalInfo,
+            const bool isUpdatable)
+            : SingleDictContent(dictPath, Ver4DictConstants::FREQ_FILE_EXTENSION, isUpdatable),
+              mHasHistoricalInfo(hasHistoricalInfo),
+              mSize(getBuffer()->getTailPosition() / getEntrySize()) {}
+
+    ProbabilityDictContent(const bool hasHistoricalInfo)
+            : mHasHistoricalInfo(hasHistoricalInfo), mSize(0) {}
+
+    const ProbabilityEntry getProbabilityEntry(const int terminalId) const;
+
+    bool setProbabilityEntry(const int terminalId, const ProbabilityEntry *const probabilityEntry);
+
+    bool flushToFile(const char *const dictPath) const;
+
+    bool runGC(const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
+            const ProbabilityDictContent *const originalProbabilityDictContent);
+
+ private:
+    DISALLOW_COPY_AND_ASSIGN(ProbabilityDictContent);
+
+    int getEntrySize() const;
+
+    int getEntryPos(const int terminalId) const;
+
+    bool writeEntry(const ProbabilityEntry *const probabilityEntry, const int entryPos);
+
+    bool mHasHistoricalInfo;
+    int mSize;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_PROBABILITY_DICT_CONTENT_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/probability_entry.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/probability_entry.h
new file mode 100644
index 0000000..d341e7b
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/probability_entry.h
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/content/probability_entry.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_PROBABILITY_ENTRY_H
+#define LATINIME_BACKWARD_V401_PROBABILITY_ENTRY_H
+
+#include "defines.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h"
+#include "suggest/policyimpl/dictionary/utils/historical_info.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+class ProbabilityEntry {
+ public:
+    ProbabilityEntry(const ProbabilityEntry &probabilityEntry)
+            : mFlags(probabilityEntry.mFlags), mProbability(probabilityEntry.mProbability),
+              mHistoricalInfo(probabilityEntry.mHistoricalInfo) {}
+
+    // Dummy entry
+    ProbabilityEntry()
+            : mFlags(0), mProbability(NOT_A_PROBABILITY), mHistoricalInfo() {}
+
+    // Entry without historical information
+    ProbabilityEntry(const int flags, const int probability)
+            : mFlags(flags), mProbability(probability), mHistoricalInfo() {}
+
+    // Entry with historical information.
+    ProbabilityEntry(const int flags, const int probability,
+            const HistoricalInfo *const historicalInfo)
+            : mFlags(flags), mProbability(probability), mHistoricalInfo(*historicalInfo) {}
+
+    const ProbabilityEntry createEntryWithUpdatedProbability(const int probability) const {
+        return ProbabilityEntry(mFlags, probability, &mHistoricalInfo);
+    }
+
+    const ProbabilityEntry createEntryWithUpdatedHistoricalInfo(
+            const HistoricalInfo *const historicalInfo) const {
+        return ProbabilityEntry(mFlags, mProbability, historicalInfo);
+    }
+
+    bool hasHistoricalInfo() const {
+        return mHistoricalInfo.isValid();
+    }
+
+    int getFlags() const {
+        return mFlags;
+    }
+
+    int getProbability() const {
+        return mProbability;
+    }
+
+    const HistoricalInfo *getHistoricalInfo() const {
+        return &mHistoricalInfo;
+    }
+
+ private:
+    // Copy constructor is public to use this class as a type of return value.
+    DISALLOW_ASSIGNMENT_OPERATOR(ProbabilityEntry);
+
+    const int mFlags;
+    const int mProbability;
+    const HistoricalInfo mHistoricalInfo;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_PROBABILITY_ENTRY_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/shortcut_dict_content.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/shortcut_dict_content.cpp
new file mode 100644
index 0000000..3214807
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/shortcut_dict_content.cpp
@@ -0,0 +1,199 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/content/shortcut_dict_content.cpp
+ */
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/shortcut_dict_content.h"
+
+#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+void ShortcutDictContent::getShortcutEntryAndAdvancePosition(const int maxCodePointCount,
+        int *const outCodePoint, int *const outCodePointCount, int *const outProbability,
+        bool *const outhasNext, int *const shortcutEntryPos) const {
+    const BufferWithExtendableBuffer *const shortcutListBuffer = getContentBuffer();
+    if (*shortcutEntryPos < 0 || *shortcutEntryPos >=  shortcutListBuffer->getTailPosition()) {
+        AKLOGE("Invalid shortcut entry position. shortcutEntryPos: %d, bufSize: %d",
+                *shortcutEntryPos, shortcutListBuffer->getTailPosition());
+        ASSERT(false);
+        if (outhasNext) {
+            *outhasNext = false;
+        }
+        if (outCodePointCount) {
+            *outCodePointCount = 0;
+        }
+        return;
+    }
+
+    const int shortcutFlags = shortcutListBuffer->readUintAndAdvancePosition(
+            Ver4DictConstants::SHORTCUT_FLAGS_FIELD_SIZE, shortcutEntryPos);
+    if (outProbability) {
+        *outProbability = shortcutFlags & Ver4DictConstants::SHORTCUT_PROBABILITY_MASK;
+    }
+    if (outhasNext) {
+        *outhasNext = shortcutFlags & Ver4DictConstants::SHORTCUT_HAS_NEXT_MASK;
+    }
+    if (outCodePoint && outCodePointCount) {
+        shortcutListBuffer->readCodePointsAndAdvancePosition(
+                maxCodePointCount, outCodePoint, outCodePointCount, shortcutEntryPos);
+    }
+}
+
+int ShortcutDictContent::getShortcutListHeadPos(const int terminalId) const {
+    const SparseTable *const addressLookupTable = getAddressLookupTable();
+    if (!addressLookupTable->contains(terminalId)) {
+        return NOT_A_DICT_POS;
+    }
+    return addressLookupTable->get(terminalId);
+}
+
+bool ShortcutDictContent::flushToFile(const char *const dictPath) const {
+    return flush(dictPath, Ver4DictConstants::SHORTCUT_LOOKUP_TABLE_FILE_EXTENSION,
+            Ver4DictConstants::SHORTCUT_CONTENT_TABLE_FILE_EXTENSION,
+            Ver4DictConstants::SHORTCUT_FILE_EXTENSION);
+}
+
+bool ShortcutDictContent::runGC(
+        const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
+        const ShortcutDictContent *const originalShortcutDictContent) {
+   for (TerminalPositionLookupTable::TerminalIdMap::const_iterator it = terminalIdMap->begin();
+           it != terminalIdMap->end(); ++it) {
+       const int originalShortcutListPos =
+               originalShortcutDictContent->getShortcutListHeadPos(it->first);
+       if (originalShortcutListPos == NOT_A_DICT_POS) {
+           continue;
+       }
+       const int shortcutListPos = getContentBuffer()->getTailPosition();
+       // Copy shortcut list from original content.
+       if (!copyShortcutListFromDictContent(originalShortcutListPos, originalShortcutDictContent,
+               shortcutListPos)) {
+           AKLOGE("Cannot copy shortcut list during GC. original pos: %d, pos: %d",
+                   originalShortcutListPos, shortcutListPos);
+           return false;
+       }
+       // Set shortcut list position to the lookup table.
+       if (!getUpdatableAddressLookupTable()->set(it->second, shortcutListPos)) {
+           AKLOGE("Cannot set shortcut list position. terminal id: %d, pos: %d",
+                   it->second, shortcutListPos);
+           return false;
+       }
+   }
+   return true;
+}
+
+bool ShortcutDictContent::createNewShortcutList(const int terminalId) {
+    const int shortcutListListPos = getContentBuffer()->getTailPosition();
+    return getUpdatableAddressLookupTable()->set(terminalId, shortcutListListPos);
+}
+
+bool ShortcutDictContent::copyShortcutList(const int shortcutListPos, const int toPos) {
+    return copyShortcutListFromDictContent(shortcutListPos, this, toPos);
+}
+
+bool ShortcutDictContent::copyShortcutListFromDictContent(const int shortcutListPos,
+        const ShortcutDictContent *const sourceShortcutDictContent, const int toPos) {
+    bool hasNext = true;
+    int readingPos = shortcutListPos;
+    int writingPos = toPos;
+    int codePoints[MAX_WORD_LENGTH];
+    while (hasNext) {
+        int probability = 0;
+        int codePointCount = 0;
+        sourceShortcutDictContent->getShortcutEntryAndAdvancePosition(MAX_WORD_LENGTH,
+                codePoints, &codePointCount, &probability, &hasNext, &readingPos);
+        if (!writeShortcutEntryAndAdvancePosition(codePoints, codePointCount, probability,
+                hasNext, &writingPos)) {
+            AKLOGE("Cannot write shortcut entry to copy. pos: %d", writingPos);
+            return false;
+        }
+    }
+    return true;
+}
+
+bool ShortcutDictContent::setProbability(const int probability, const int shortcutEntryPos) {
+    BufferWithExtendableBuffer *const shortcutListBuffer = getWritableContentBuffer();
+    const int shortcutFlags = shortcutListBuffer->readUint(
+            Ver4DictConstants::SHORTCUT_FLAGS_FIELD_SIZE, shortcutEntryPos);
+    const bool hasNext = shortcutFlags & Ver4DictConstants::SHORTCUT_HAS_NEXT_MASK;
+    const int shortcutFlagsToWrite = createAndGetShortcutFlags(probability, hasNext);
+    return shortcutListBuffer->writeUint(shortcutFlagsToWrite,
+            Ver4DictConstants::SHORTCUT_FLAGS_FIELD_SIZE, shortcutEntryPos);
+}
+
+bool ShortcutDictContent::writeShortcutEntryAndAdvancePosition(const int *const codePoint,
+        const int codePointCount, const int probability, const bool hasNext,
+        int *const shortcutEntryPos) {
+    BufferWithExtendableBuffer *const shortcutListBuffer = getWritableContentBuffer();
+    const int shortcutFlags = createAndGetShortcutFlags(probability, hasNext);
+    if (!shortcutListBuffer->writeUintAndAdvancePosition(shortcutFlags,
+            Ver4DictConstants::SHORTCUT_FLAGS_FIELD_SIZE, shortcutEntryPos)) {
+        AKLOGE("Cannot write shortcut flags. flags; %x, pos: %d", shortcutFlags, *shortcutEntryPos);
+        return false;
+    }
+    if (!shortcutListBuffer->writeCodePointsAndAdvancePosition(codePoint, codePointCount,
+            true /* writesTerminator */, shortcutEntryPos)) {
+        AKLOGE("Cannot write shortcut target code points. pos: %d", *shortcutEntryPos);
+        return false;
+    }
+    return true;
+}
+
+// Find a shortcut entry that has specified target and return its position.
+int ShortcutDictContent::findShortcutEntryAndGetPos(const int shortcutListPos,
+        const int *const targetCodePointsToFind, const int codePointCount) const {
+    bool hasNext = true;
+    int readingPos = shortcutListPos;
+    int targetCodePoints[MAX_WORD_LENGTH];
+    while (hasNext) {
+        const int entryPos = readingPos;
+        int probability = 0;
+        int targetCodePointCount = 0;
+        getShortcutEntryAndAdvancePosition(MAX_WORD_LENGTH, targetCodePoints, &targetCodePointCount,
+                &probability, &hasNext, &readingPos);
+        if (targetCodePointCount != codePointCount) {
+            continue;
+        }
+        bool matched = true;
+        for (int i = 0; i < codePointCount; ++i) {
+            if (targetCodePointsToFind[i] != targetCodePoints[i]) {
+                matched = false;
+                break;
+            }
+        }
+        if (matched) {
+            return entryPos;
+        }
+    }
+    return NOT_A_DICT_POS;
+}
+
+int ShortcutDictContent::createAndGetShortcutFlags(const int probability,
+        const bool hasNext) const {
+    return (probability & Ver4DictConstants::SHORTCUT_PROBABILITY_MASK)
+            | (hasNext ? Ver4DictConstants::SHORTCUT_HAS_NEXT_MASK : 0);
+}
+
+} // namespace v401
+} // namespace backward
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/shortcut_dict_content.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/shortcut_dict_content.h
new file mode 100644
index 0000000..75fd4f3
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/shortcut_dict_content.h
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/content/shortcut_dict_content.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_SHORTCUT_DICT_CONTENT_H
+#define LATINIME_BACKWARD_V401_SHORTCUT_DICT_CONTENT_H
+
+#include "defines.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/sparse_table_dict_content.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+class ShortcutDictContent : public SparseTableDictContent {
+ public:
+    ShortcutDictContent(const char *const dictPath, const bool isUpdatable)
+            : SparseTableDictContent(dictPath,
+                      Ver4DictConstants::SHORTCUT_LOOKUP_TABLE_FILE_EXTENSION,
+                      Ver4DictConstants::SHORTCUT_CONTENT_TABLE_FILE_EXTENSION,
+                      Ver4DictConstants::SHORTCUT_FILE_EXTENSION, isUpdatable,
+                      Ver4DictConstants::SHORTCUT_ADDRESS_TABLE_BLOCK_SIZE,
+                      Ver4DictConstants::SHORTCUT_ADDRESS_TABLE_DATA_SIZE) {}
+
+    ShortcutDictContent()
+            : SparseTableDictContent(Ver4DictConstants::SHORTCUT_ADDRESS_TABLE_BLOCK_SIZE,
+                      Ver4DictConstants::SHORTCUT_ADDRESS_TABLE_DATA_SIZE) {}
+
+    void getShortcutEntry(const int maxCodePointCount, int *const outCodePoint,
+            int *const outCodePointCount, int *const outProbability, bool *const outhasNext,
+            const int shortcutEntryPos) {
+        int readingPos = shortcutEntryPos;
+        return getShortcutEntryAndAdvancePosition(maxCodePointCount, outCodePoint,
+                outCodePointCount, outProbability, outhasNext, &readingPos);
+    }
+
+    void getShortcutEntryAndAdvancePosition(const int maxCodePointCount,
+            int *const outCodePoint, int *const outCodePointCount, int *const outProbability,
+            bool *const outhasNext, int *const shortcutEntryPos) const;
+
+   // Returns head position of shortcut list for a PtNode specified by terminalId.
+   int getShortcutListHeadPos(const int terminalId) const;
+
+   bool flushToFile(const char *const dictPath) const;
+
+   bool runGC(const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap,
+           const ShortcutDictContent *const originalShortcutDictContent);
+
+   bool createNewShortcutList(const int terminalId);
+
+   bool copyShortcutList(const int shortcutListPos, const int toPos);
+
+   bool setProbability(const int probability, const int shortcutEntryPos);
+
+   bool writeShortcutEntry(const int *const codePoint, const int codePointCount,
+           const int probability, const bool hasNext, const int shortcutEntryPos) {
+       int writingPos = shortcutEntryPos;
+       return writeShortcutEntryAndAdvancePosition(codePoint, codePointCount, probability,
+               hasNext, &writingPos);
+   }
+
+   bool writeShortcutEntryAndAdvancePosition(const int *const codePoint,
+           const int codePointCount, const int probability, const bool hasNext,
+           int *const shortcutEntryPos);
+
+   int findShortcutEntryAndGetPos(const int shortcutListPos,
+           const int *const targetCodePointsToFind, const int codePointCount) const;
+
+ private:
+    DISALLOW_COPY_AND_ASSIGN(ShortcutDictContent);
+
+    bool copyShortcutListFromDictContent(const int shortcutListPos,
+            const ShortcutDictContent *const sourceShortcutDictContent, const int toPos);
+
+    int createAndGetShortcutFlags(const int probability, const bool hasNext) const;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_SHORTCUT_DICT_CONTENT_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/single_dict_content.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/single_dict_content.h
new file mode 100644
index 0000000..a519cd8
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/single_dict_content.h
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/content/single_dict_content.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_SINGLE_DICT_CONTENT_H
+#define LATINIME_BACKWARD_V401_SINGLE_DICT_CONTENT_H
+
+#include "defines.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/dict_content.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h"
+#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h"
+#include "suggest/policyimpl/dictionary/utils/mmapped_buffer.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+class SingleDictContent : public DictContent {
+ public:
+    SingleDictContent(const char *const dictPath, const char *const contentFileName,
+            const bool isUpdatable)
+            : mMmappedBuffer(MmappedBuffer::openBuffer(dictPath, contentFileName, isUpdatable)),
+              mExpandableContentBuffer(mMmappedBuffer ? mMmappedBuffer->getBuffer() : nullptr,
+                      mMmappedBuffer ? mMmappedBuffer->getBufferSize() : 0,
+                      BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
+              mIsValid(mMmappedBuffer) {}
+
+    SingleDictContent()
+            : mMmappedBuffer(nullptr),
+              mExpandableContentBuffer(Ver4DictConstants::MAX_DICTIONARY_SIZE), mIsValid(true) {}
+
+    virtual ~SingleDictContent() {}
+
+    virtual bool isValid() const {
+        return mIsValid;
+    }
+
+    bool isNearSizeLimit() const {
+        return mExpandableContentBuffer.isNearSizeLimit();
+    }
+
+ protected:
+    BufferWithExtendableBuffer *getWritableBuffer() {
+        return &mExpandableContentBuffer;
+    }
+
+    const BufferWithExtendableBuffer *getBuffer() const {
+        return &mExpandableContentBuffer;
+    }
+
+    bool flush(const char *const dictPath, const char *const contentFileNameSuffix) const {
+        return DictFileWritingUtils::flushBufferToFileWithSuffix(dictPath,
+                contentFileNameSuffix, &mExpandableContentBuffer);
+    }
+
+ private:
+    DISALLOW_COPY_AND_ASSIGN(SingleDictContent);
+
+    const MmappedBuffer::MmappedBufferPtr mMmappedBuffer;
+    BufferWithExtendableBuffer mExpandableContentBuffer;
+    const bool mIsValid;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_SINGLE_DICT_CONTENT_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/sparse_table_dict_content.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/sparse_table_dict_content.cpp
new file mode 100644
index 0000000..638132c
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/sparse_table_dict_content.cpp
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.cpp
+ */
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/sparse_table_dict_content.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+bool SparseTableDictContent::flush(const char *const dictPath,
+        const char *const lookupTableFileNameSuffix, const char *const addressTableFileNameSuffix,
+        const char *const contentFileNameSuffix) const {
+    if (!DictFileWritingUtils::flushBufferToFileWithSuffix(dictPath, lookupTableFileNameSuffix,
+            &mExpandableLookupTableBuffer)){
+        return false;
+    }
+    if (!DictFileWritingUtils::flushBufferToFileWithSuffix(dictPath, addressTableFileNameSuffix,
+            &mExpandableAddressTableBuffer)) {
+        return false;
+    }
+    if (!DictFileWritingUtils::flushBufferToFileWithSuffix(dictPath, contentFileNameSuffix,
+            &mExpandableContentBuffer)) {
+        return false;
+    }
+    return true;
+}
+
+} // namespace v401
+} // namespace backward
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/sparse_table_dict_content.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/sparse_table_dict_content.h
new file mode 100644
index 0000000..b95de2e
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/sparse_table_dict_content.h
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/content/sparse_table_dict_content.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_SPARSE_TABLE_DICT_CONTENT_H
+#define LATINIME_BACKWARD_V401_SPARSE_TABLE_DICT_CONTENT_H
+
+#include "defines.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/dict_content.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h"
+#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h"
+#include "suggest/policyimpl/dictionary/utils/mmapped_buffer.h"
+#include "suggest/policyimpl/dictionary/utils/sparse_table.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+// TODO: Support multiple contents.
+class SparseTableDictContent : public DictContent {
+ public:
+    AK_FORCE_INLINE SparseTableDictContent(const char *const dictPath,
+            const char *const lookupTableFileName, const char *const addressTableFileName,
+            const char *const contentFileName, const bool isUpdatable,
+            const int sparseTableBlockSize, const int sparseTableDataSize)
+            : mLookupTableBuffer(
+                      MmappedBuffer::openBuffer(dictPath, lookupTableFileName, isUpdatable)),
+              mAddressTableBuffer(
+                      MmappedBuffer::openBuffer(dictPath, addressTableFileName, isUpdatable)),
+              mContentBuffer(
+                      MmappedBuffer::openBuffer(dictPath, contentFileName, isUpdatable)),
+              mExpandableLookupTableBuffer(
+                      mLookupTableBuffer ? mLookupTableBuffer->getBuffer() : nullptr,
+                      mLookupTableBuffer ? mLookupTableBuffer->getBufferSize() : 0,
+                      BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
+              mExpandableAddressTableBuffer(
+                      mAddressTableBuffer ? mAddressTableBuffer->getBuffer() : nullptr,
+                      mAddressTableBuffer ? mAddressTableBuffer->getBufferSize() : 0,
+                      BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
+              mExpandableContentBuffer(mContentBuffer ? mContentBuffer->getBuffer() : nullptr,
+                      mContentBuffer ? mContentBuffer->getBufferSize() : 0,
+                      BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
+              mAddressLookupTable(&mExpandableLookupTableBuffer, &mExpandableAddressTableBuffer,
+                      sparseTableBlockSize, sparseTableDataSize),
+              mIsValid(mLookupTableBuffer && mAddressTableBuffer && mContentBuffer) {}
+
+    SparseTableDictContent(const int sparseTableBlockSize, const int sparseTableDataSize)
+            : mLookupTableBuffer(), mAddressTableBuffer(), mContentBuffer(),
+              mExpandableLookupTableBuffer(Ver4DictConstants::MAX_DICTIONARY_SIZE),
+              mExpandableAddressTableBuffer(Ver4DictConstants::MAX_DICTIONARY_SIZE),
+              mExpandableContentBuffer(Ver4DictConstants::MAX_DICTIONARY_SIZE),
+              mAddressLookupTable(&mExpandableLookupTableBuffer, &mExpandableAddressTableBuffer,
+                      sparseTableBlockSize, sparseTableDataSize), mIsValid(true) {}
+
+    virtual ~SparseTableDictContent() {}
+
+    virtual bool isValid() const {
+        return mIsValid;
+    }
+
+    bool isNearSizeLimit() const {
+        return mExpandableLookupTableBuffer.isNearSizeLimit()
+                || mExpandableAddressTableBuffer.isNearSizeLimit()
+                || mExpandableContentBuffer.isNearSizeLimit();
+    }
+
+ protected:
+    SparseTable *getUpdatableAddressLookupTable() {
+        return &mAddressLookupTable;
+    }
+
+    const SparseTable *getAddressLookupTable() const {
+        return &mAddressLookupTable;
+    }
+
+    BufferWithExtendableBuffer *getWritableContentBuffer() {
+        return &mExpandableContentBuffer;
+    }
+
+    const BufferWithExtendableBuffer *getContentBuffer() const {
+        return &mExpandableContentBuffer;
+    }
+
+    bool flush(const char *const dictDirPath, const char *const lookupTableFileName,
+            const char *const addressTableFileName, const char *const contentFileName) const;
+
+ private:
+    DISALLOW_IMPLICIT_CONSTRUCTORS(SparseTableDictContent);
+
+    const MmappedBuffer::MmappedBufferPtr mLookupTableBuffer;
+    const MmappedBuffer::MmappedBufferPtr mAddressTableBuffer;
+    const MmappedBuffer::MmappedBufferPtr mContentBuffer;
+    BufferWithExtendableBuffer mExpandableLookupTableBuffer;
+    BufferWithExtendableBuffer mExpandableAddressTableBuffer;
+    BufferWithExtendableBuffer mExpandableContentBuffer;
+    SparseTable mAddressLookupTable;
+    const bool mIsValid;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_SPARSE_TABLE_DICT_CONTENT_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.cpp
new file mode 100644
index 0000000..ab8a3ae
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.cpp
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.cpp
+ */
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.h"
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_reading_utils.h"
+#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+int TerminalPositionLookupTable::getTerminalPtNodePosition(const int terminalId) const {
+    if (terminalId < 0 || terminalId >= mSize) {
+        return NOT_A_DICT_POS;
+    }
+    const int terminalPos = getBuffer()->readUint(
+            Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE, getEntryPos(terminalId));
+    return (terminalPos == Ver4DictConstants::NOT_A_TERMINAL_ADDRESS) ?
+            NOT_A_DICT_POS : terminalPos;
+}
+
+bool TerminalPositionLookupTable::setTerminalPtNodePosition(
+        const int terminalId, const int terminalPtNodePos) {
+    if (terminalId < 0) {
+        return NOT_A_DICT_POS;
+    }
+    while (terminalId >= mSize) {
+        // Write new entry.
+        if (!getWritableBuffer()->writeUint(Ver4DictConstants::NOT_A_TERMINAL_ADDRESS,
+                Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE, getEntryPos(mSize))) {
+            return false;
+        }
+        mSize++;
+    }
+    const int terminalPos = (terminalPtNodePos != NOT_A_DICT_POS) ?
+            terminalPtNodePos : Ver4DictConstants::NOT_A_TERMINAL_ADDRESS;
+    return getWritableBuffer()->writeUint(terminalPos,
+            Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE, getEntryPos(terminalId));
+}
+
+bool TerminalPositionLookupTable::flushToFile(const char *const dictPath) const {
+    // If the used buffer size is smaller than the actual buffer size, regenerate the lookup
+    // table and write the new table to the file.
+    if (getEntryPos(mSize) < getBuffer()->getTailPosition()) {
+        TerminalPositionLookupTable lookupTableToWrite;
+        for (int i = 0; i < mSize; ++i) {
+            const int terminalPtNodePosition = getTerminalPtNodePosition(i);
+            if (!lookupTableToWrite.setTerminalPtNodePosition(i, terminalPtNodePosition)) {
+                AKLOGE("Cannot set terminal position to lookupTableToWrite."
+                        " terminalId: %d, position: %d", i, terminalPtNodePosition);
+                return false;
+            }
+        }
+        return lookupTableToWrite.flush(dictPath,
+                Ver4DictConstants::TERMINAL_ADDRESS_TABLE_FILE_EXTENSION);
+    } else {
+        // We can simply use this lookup table because the buffer size has not been
+        // changed.
+        return flush(dictPath, Ver4DictConstants::TERMINAL_ADDRESS_TABLE_FILE_EXTENSION);
+    }
+}
+
+bool TerminalPositionLookupTable::runGCTerminalIds(TerminalIdMap *const terminalIdMap) {
+    int removedEntryCount = 0;
+    int nextNewTerminalId = 0;
+    for (int i = 0; i < mSize; ++i) {
+        const int terminalPos = getBuffer()->readUint(
+                Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE, getEntryPos(i));
+        if (terminalPos == Ver4DictConstants::NOT_A_TERMINAL_ADDRESS) {
+            // This entry is a garbage.
+            removedEntryCount++;
+        } else {
+            // Give a new terminal id to the entry.
+            if (!getWritableBuffer()->writeUint(terminalPos,
+                    Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE,
+                    getEntryPos(nextNewTerminalId))) {
+                return false;
+            }
+            // Memorize the mapping to the old terminal id to the new terminal id.
+            terminalIdMap->insert(TerminalIdMap::value_type(i, nextNewTerminalId));
+            nextNewTerminalId++;
+        }
+    }
+    mSize = nextNewTerminalId;
+    return true;
+}
+
+} // namespace v401
+} // namespace backward
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.h
new file mode 100644
index 0000000..dbf0e60
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.h
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/content/terminal_position_lookup_table.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_TERMINAL_POSITION_LOOKUP_TABLE_H
+#define LATINIME_BACKWARD_V401_TERMINAL_POSITION_LOOKUP_TABLE_H
+
+#include <unordered_map>
+
+#include "defines.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/single_dict_content.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+class TerminalPositionLookupTable : public SingleDictContent {
+ public:
+    typedef std::unordered_map<int, int> TerminalIdMap;
+
+    TerminalPositionLookupTable(const char *const dictPath, const bool isUpdatable)
+            : SingleDictContent(dictPath,
+                      Ver4DictConstants::TERMINAL_ADDRESS_TABLE_FILE_EXTENSION, isUpdatable),
+              mSize(getBuffer()->getTailPosition()
+                      / Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE) {}
+
+    TerminalPositionLookupTable() : mSize(0) {}
+
+    int getTerminalPtNodePosition(const int terminalId) const;
+
+    bool setTerminalPtNodePosition(const int terminalId, const int terminalPtNodePos);
+
+    int getNextTerminalId() const {
+        return mSize;
+    }
+
+    bool flushToFile(const char *const dictPath) const;
+
+    bool runGCTerminalIds(TerminalIdMap *const terminalIdMap);
+
+ private:
+    DISALLOW_COPY_AND_ASSIGN(TerminalPositionLookupTable);
+
+    int getEntryPos(const int terminalId) const {
+        return terminalId * Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE;
+    }
+
+    int mSize;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif // LATINIME_BACKWARD_V401_TERMINAL_POSITION_LOOKUP_TABLE_H
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/shortcut/ver4_shortcut_list_policy.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/shortcut/ver4_shortcut_list_policy.h
new file mode 100644
index 0000000..6a4e83c
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/shortcut/ver4_shortcut_list_policy.h
@@ -0,0 +1,118 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT CHANGE THE LOGIC IN THIS FILE !!!!!
+ * Do not edit this file other than updating policy's interface.
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/shortcut/ver4_shortcut_list_policy.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_VER4_SHORTCUT_LIST_POLICY_H
+#define LATINIME_BACKWARD_V401_VER4_SHORTCUT_LIST_POLICY_H
+
+#include "defines.h"
+#include "suggest/core/policy/dictionary_shortcuts_structure_policy.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/shortcut/shortcut_list_reading_utils.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/shortcut_dict_content.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+class Ver4ShortcutListPolicy : public DictionaryShortcutsStructurePolicy {
+ public:
+    Ver4ShortcutListPolicy(ShortcutDictContent *const shortcutDictContent,
+            const TerminalPositionLookupTable *const terminalPositionLookupTable)
+            : mShortcutDictContent(shortcutDictContent) {}
+
+    ~Ver4ShortcutListPolicy() {}
+
+    int getStartPos(const int pos) const {
+        // The first shortcut entry is located at the head position of the shortcut list.
+        return pos;
+    }
+
+    void getNextShortcut(const int maxCodePointCount, int *const outCodePoint,
+            int *const outCodePointCount, bool *const outIsWhitelist, bool *const outHasNext,
+            int *const pos) const {
+        int probability = 0;
+        mShortcutDictContent->getShortcutEntryAndAdvancePosition(maxCodePointCount,
+                outCodePoint, outCodePointCount, &probability, outHasNext, pos);
+        if (outIsWhitelist) {
+            *outIsWhitelist = ShortcutListReadingUtils::isWhitelist(probability);
+        }
+    }
+
+    void skipAllShortcuts(int *const pos) const {
+        // Do nothing because we don't need to skip shortcut lists in ver4 dictionaries.
+    }
+
+    bool addNewShortcut(const int terminalId, const int *const codePoints, const int codePointCount,
+            const int probability) {
+        const int shortcutListPos = mShortcutDictContent->getShortcutListHeadPos(terminalId);
+        if (shortcutListPos == NOT_A_DICT_POS) {
+            // Create shortcut list.
+            if (!mShortcutDictContent->createNewShortcutList(terminalId)) {
+                AKLOGE("Cannot create new shortcut list. terminal id: %d", terminalId);
+                return false;
+            }
+            const int writingPos =  mShortcutDictContent->getShortcutListHeadPos(terminalId);
+            return mShortcutDictContent->writeShortcutEntry(codePoints, codePointCount, probability,
+                    false /* hasNext */, writingPos);
+        }
+        const int entryPos = mShortcutDictContent->findShortcutEntryAndGetPos(shortcutListPos,
+                codePoints, codePointCount);
+        if (entryPos == NOT_A_DICT_POS) {
+            // Add new entry to the shortcut list.
+            // Create new shortcut list.
+            if (!mShortcutDictContent->createNewShortcutList(terminalId)) {
+                AKLOGE("Cannot create new shortcut list. terminal id: %d", terminalId);
+                return false;
+            }
+            int writingPos =  mShortcutDictContent->getShortcutListHeadPos(terminalId);
+            if (!mShortcutDictContent->writeShortcutEntryAndAdvancePosition(codePoints,
+                    codePointCount, probability, true /* hasNext */, &writingPos)) {
+                AKLOGE("Cannot write shortcut entry. terminal id: %d, pos: %d", terminalId,
+                        writingPos);
+                return false;
+            }
+            return mShortcutDictContent->copyShortcutList(shortcutListPos, writingPos);
+        }
+        // Overwrite existing entry.
+        bool hasNext = false;
+        mShortcutDictContent->getShortcutEntry(MAX_WORD_LENGTH, 0 /* outCodePoint */,
+                0 /* outCodePointCount */ , 0 /* probability */, &hasNext, entryPos);
+        if (!mShortcutDictContent->writeShortcutEntry(codePoints,
+                codePointCount, probability, hasNext, entryPos)) {
+            AKLOGE("Cannot overwrite shortcut entry. terminal id: %d, pos: %d", terminalId,
+                    entryPos);
+            return false;
+        }
+        return true;
+    }
+
+ private:
+    DISALLOW_IMPLICIT_CONSTRUCTORS(Ver4ShortcutListPolicy);
+
+    ShortcutDictContent *const mShortcutDictContent;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif // LATINIME_BACKWARD_V401_VER4_SHORTCUT_LIST_POLICY_H
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_buffers.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_buffers.cpp
new file mode 100644
index 0000000..55ead01
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_buffers.cpp
@@ -0,0 +1,155 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp
+ */
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_buffers.h"
+
+#include <cerrno>
+#include <cstring>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include "suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h"
+#include "suggest/policyimpl/dictionary/utils/file_utils.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+/* static */ Ver4DictBuffers::Ver4DictBuffersPtr Ver4DictBuffers::openVer4DictBuffers(
+        const char *const dictPath, MmappedBuffer::MmappedBufferPtr headerBuffer,
+        const FormatUtils::FORMAT_VERSION formatVersion) {
+    if (!headerBuffer) {
+        ASSERT(false);
+        AKLOGE("The header buffer must be valid to open ver4 dict buffers.");
+        return Ver4DictBuffersPtr(nullptr);
+    }
+    // TODO: take only dictDirPath, and open both header and trie files in the constructor below
+    const bool isUpdatable = headerBuffer->isUpdatable();
+    return Ver4DictBuffersPtr(new Ver4DictBuffers(dictPath, std::move(headerBuffer), isUpdatable,
+            formatVersion));
+}
+
+bool Ver4DictBuffers::flushHeaderAndDictBuffers(const char *const dictDirPath,
+        const BufferWithExtendableBuffer *const headerBuffer) const {
+    // Create temporary directory.
+    const int tmpDirPathBufSize = FileUtils::getFilePathWithSuffixBufSize(dictDirPath,
+            DictFileWritingUtils::TEMP_FILE_SUFFIX_FOR_WRITING_DICT_FILE);
+    char tmpDirPath[tmpDirPathBufSize];
+    FileUtils::getFilePathWithSuffix(dictDirPath,
+            DictFileWritingUtils::TEMP_FILE_SUFFIX_FOR_WRITING_DICT_FILE, tmpDirPathBufSize,
+            tmpDirPath);
+    if (FileUtils::existsDir(tmpDirPath)) {
+        if (!FileUtils::removeDirAndFiles(tmpDirPath)) {
+            AKLOGE("Existing directory %s cannot be removed.", tmpDirPath);
+            ASSERT(false);
+            return false;
+        }
+    }
+    if (mkdir(tmpDirPath, S_IRWXU) == -1) {
+        AKLOGE("Cannot create directory: %s. errno: %d.", tmpDirPath, errno);
+        return false;
+    }
+    // Get dictionary base path.
+    const int dictNameBufSize = strlen(dictDirPath) + 1 /* terminator */;
+    char dictName[dictNameBufSize];
+    FileUtils::getBasename(dictDirPath, dictNameBufSize, dictName);
+    const int dictPathBufSize = FileUtils::getFilePathBufSize(tmpDirPath, dictName);
+    char dictPath[dictPathBufSize];
+    FileUtils::getFilePath(tmpDirPath, dictName, dictPathBufSize, dictPath);
+
+    // Write header file.
+    if (!DictFileWritingUtils::flushBufferToFileWithSuffix(dictPath,
+            Ver4DictConstants::HEADER_FILE_EXTENSION, headerBuffer)) {
+        AKLOGE("Dictionary header file %s%s cannot be written.", tmpDirPath,
+                Ver4DictConstants::HEADER_FILE_EXTENSION);
+        return false;
+    }
+    // Write trie file.
+    if (!DictFileWritingUtils::flushBufferToFileWithSuffix(dictPath,
+            Ver4DictConstants::TRIE_FILE_EXTENSION, &mExpandableTrieBuffer)) {
+        AKLOGE("Dictionary trie file %s%s cannot be written.", tmpDirPath,
+                Ver4DictConstants::TRIE_FILE_EXTENSION);
+        return false;
+    }
+    // Write dictionary contents.
+    if (!mTerminalPositionLookupTable.flushToFile(dictPath)) {
+        AKLOGE("Terminal position lookup table cannot be written. %s", tmpDirPath);
+        return false;
+    }
+    if (!mProbabilityDictContent.flushToFile(dictPath)) {
+        AKLOGE("Probability dict content cannot be written. %s", tmpDirPath);
+        return false;
+    }
+    if (!mBigramDictContent.flushToFile(dictPath)) {
+        AKLOGE("Bigram dict content cannot be written. %s", tmpDirPath);
+        return false;
+    }
+    if (!mShortcutDictContent.flushToFile(dictPath)) {
+        AKLOGE("Shortcut dict content cannot be written. %s", tmpDirPath);
+        return false;
+    }
+    // Remove existing dictionary.
+    if (!FileUtils::removeDirAndFiles(dictDirPath)) {
+        AKLOGE("Existing directory %s cannot be removed.", dictDirPath);
+        ASSERT(false);
+        return false;
+    }
+    // Rename temporary directory.
+    if (rename(tmpDirPath, dictDirPath) != 0) {
+        AKLOGE("%s cannot be renamed to %s", tmpDirPath, dictDirPath);
+        ASSERT(false);
+        return false;
+    }
+    return true;
+}
+
+Ver4DictBuffers::Ver4DictBuffers(const char *const dictPath,
+        MmappedBuffer::MmappedBufferPtr headerBuffer, const bool isUpdatable,
+        const FormatUtils::FORMAT_VERSION formatVersion)
+        : mHeaderBuffer(std::move(headerBuffer)),
+          mDictBuffer(MmappedBuffer::openBuffer(dictPath,
+                  Ver4DictConstants::TRIE_FILE_EXTENSION, isUpdatable)),
+          mHeaderPolicy(mHeaderBuffer->getBuffer(), formatVersion),
+          mExpandableHeaderBuffer(mHeaderBuffer ? mHeaderBuffer->getBuffer() : nullptr,
+                  mHeaderPolicy.getSize(),
+                  BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
+          mExpandableTrieBuffer(mDictBuffer ? mDictBuffer->getBuffer() : nullptr,
+                  mDictBuffer ? mDictBuffer->getBufferSize() : 0,
+                  BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE),
+          mTerminalPositionLookupTable(dictPath, isUpdatable),
+          mProbabilityDictContent(dictPath, mHeaderPolicy.hasHistoricalInfoOfWords(), isUpdatable),
+          mBigramDictContent(dictPath, mHeaderPolicy.hasHistoricalInfoOfWords(), isUpdatable),
+          mShortcutDictContent(dictPath, isUpdatable),
+          mIsUpdatable(isUpdatable) {}
+
+Ver4DictBuffers::Ver4DictBuffers(const HeaderPolicy *const headerPolicy, const int maxTrieSize)
+        : mHeaderBuffer(nullptr), mDictBuffer(nullptr), mHeaderPolicy(headerPolicy),
+          mExpandableHeaderBuffer(Ver4DictConstants::MAX_DICTIONARY_SIZE),
+          mExpandableTrieBuffer(maxTrieSize), mTerminalPositionLookupTable(),
+          mProbabilityDictContent(headerPolicy->hasHistoricalInfoOfWords()),
+          mBigramDictContent(headerPolicy->hasHistoricalInfoOfWords()), mShortcutDictContent(),
+          mIsUpdatable(true) {}
+
+} // namespace v401
+} // namespace backward
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_buffers.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_buffers.h
new file mode 100644
index 0000000..716ed93
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_buffers.h
@@ -0,0 +1,152 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_VER4_DICT_BUFFER_H
+#define LATINIME_BACKWARD_V401_VER4_DICT_BUFFER_H
+
+#include <memory>
+
+#include "defines.h"
+#include "suggest/policyimpl/dictionary/header/header_policy.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/bigram_dict_content.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/probability_dict_content.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/shortcut_dict_content.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h"
+#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "suggest/policyimpl/dictionary/utils/mmapped_buffer.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+class Ver4DictBuffers {
+ public:
+    typedef std::unique_ptr<Ver4DictBuffers> Ver4DictBuffersPtr;
+
+    static Ver4DictBuffersPtr openVer4DictBuffers(const char *const dictDirPath,
+            MmappedBuffer::MmappedBufferPtr headerBuffer,
+            const FormatUtils::FORMAT_VERSION formatVersion);
+
+    static AK_FORCE_INLINE Ver4DictBuffersPtr createVer4DictBuffers(
+            const HeaderPolicy *const headerPolicy, const int maxTrieSize) {
+        return Ver4DictBuffersPtr(new Ver4DictBuffers(headerPolicy, maxTrieSize));
+    }
+
+    AK_FORCE_INLINE bool isValid() const {
+        return mHeaderBuffer && mDictBuffer && mHeaderPolicy.isValid()
+                && mProbabilityDictContent.isValid() && mTerminalPositionLookupTable.isValid()
+                && mBigramDictContent.isValid() && mShortcutDictContent.isValid();
+    }
+
+    AK_FORCE_INLINE bool isNearSizeLimit() const {
+        return mExpandableTrieBuffer.isNearSizeLimit()
+                || mTerminalPositionLookupTable.isNearSizeLimit()
+                || mProbabilityDictContent.isNearSizeLimit()
+                || mBigramDictContent.isNearSizeLimit()
+                || mShortcutDictContent.isNearSizeLimit();
+    }
+
+    AK_FORCE_INLINE const HeaderPolicy *getHeaderPolicy() const {
+        return &mHeaderPolicy;
+    }
+
+    AK_FORCE_INLINE BufferWithExtendableBuffer *getWritableHeaderBuffer() {
+        return &mExpandableHeaderBuffer;
+    }
+
+    AK_FORCE_INLINE BufferWithExtendableBuffer *getWritableTrieBuffer() {
+        return &mExpandableTrieBuffer;
+    }
+
+    AK_FORCE_INLINE const BufferWithExtendableBuffer *getTrieBuffer() const {
+        return &mExpandableTrieBuffer;
+    }
+
+    AK_FORCE_INLINE TerminalPositionLookupTable *getMutableTerminalPositionLookupTable() {
+        return &mTerminalPositionLookupTable;
+    }
+
+    AK_FORCE_INLINE const TerminalPositionLookupTable *getTerminalPositionLookupTable() const {
+        return &mTerminalPositionLookupTable;
+    }
+
+    AK_FORCE_INLINE ProbabilityDictContent *getMutableProbabilityDictContent() {
+        return &mProbabilityDictContent;
+    }
+
+    AK_FORCE_INLINE const ProbabilityDictContent *getProbabilityDictContent() const {
+        return &mProbabilityDictContent;
+    }
+
+    AK_FORCE_INLINE BigramDictContent *getMutableBigramDictContent() {
+        return &mBigramDictContent;
+    }
+
+    AK_FORCE_INLINE const BigramDictContent *getBigramDictContent() const {
+        return &mBigramDictContent;
+    }
+
+    AK_FORCE_INLINE ShortcutDictContent *getMutableShortcutDictContent() {
+        return &mShortcutDictContent;
+    }
+
+    AK_FORCE_INLINE const ShortcutDictContent *getShortcutDictContent() const {
+        return &mShortcutDictContent;
+    }
+
+    AK_FORCE_INLINE bool isUpdatable() const {
+        return mIsUpdatable;
+    }
+
+    bool flush(const char *const dictDirPath) const {
+        return flushHeaderAndDictBuffers(dictDirPath, &mExpandableHeaderBuffer);
+    }
+
+    bool flushHeaderAndDictBuffers(const char *const dictDirPath,
+            const BufferWithExtendableBuffer *const headerBuffer) const;
+
+ private:
+    DISALLOW_COPY_AND_ASSIGN(Ver4DictBuffers);
+
+    Ver4DictBuffers(const char *const dictDirPath,
+            const MmappedBuffer::MmappedBufferPtr headerBuffer, const bool isUpdatable,
+            const FormatUtils::FORMAT_VERSION formatVersion);
+
+    Ver4DictBuffers(const HeaderPolicy *const headerPolicy, const int maxTrieSize);
+
+    const MmappedBuffer::MmappedBufferPtr mHeaderBuffer;
+    const MmappedBuffer::MmappedBufferPtr mDictBuffer;
+    const HeaderPolicy mHeaderPolicy;
+    BufferWithExtendableBuffer mExpandableHeaderBuffer;
+    BufferWithExtendableBuffer mExpandableTrieBuffer;
+    TerminalPositionLookupTable mTerminalPositionLookupTable;
+    ProbabilityDictContent mProbabilityDictContent;
+    BigramDictContent mBigramDictContent;
+    ShortcutDictContent mShortcutDictContent;
+    const int mIsUpdatable;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_VER4_DICT_BUFFER_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.cpp
new file mode 100644
index 0000000..793b44e
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.cpp
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.cpp
+ */
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+// These values MUST match the definitions in FormatSpec.java.
+const char *const Ver4DictConstants::TRIE_FILE_EXTENSION = ".trie";
+const char *const Ver4DictConstants::HEADER_FILE_EXTENSION = ".header";
+const char *const Ver4DictConstants::FREQ_FILE_EXTENSION = ".freq";
+// tat = Terminal Address Table
+const char *const Ver4DictConstants::TERMINAL_ADDRESS_TABLE_FILE_EXTENSION = ".tat";
+const char *const Ver4DictConstants::BIGRAM_FILE_EXTENSION = ".bigram_freq";
+const char *const Ver4DictConstants::BIGRAM_LOOKUP_TABLE_FILE_EXTENSION = ".bigram_lookup";
+const char *const Ver4DictConstants::BIGRAM_CONTENT_TABLE_FILE_EXTENSION = ".bigram_index_freq";
+const char *const Ver4DictConstants::SHORTCUT_FILE_EXTENSION = ".shortcut_shortcut";
+const char *const Ver4DictConstants::SHORTCUT_LOOKUP_TABLE_FILE_EXTENSION = ".shortcut_lookup";
+const char *const Ver4DictConstants::SHORTCUT_CONTENT_TABLE_FILE_EXTENSION =
+        ".shortcut_index_shortcut";
+
+// Version 4 dictionary size is implicitly limited to 8MB due to 3-byte offsets.
+const int Ver4DictConstants::MAX_DICTIONARY_SIZE = 8 * 1024 * 1024;
+// Extended region size, which is not GCed region size in dict file + additional buffer size, is
+// limited to 1MB to prevent from inefficient traversing.
+const int Ver4DictConstants::MAX_DICT_EXTENDED_REGION_SIZE = 1 * 1024 * 1024;
+
+const int Ver4DictConstants::NOT_A_TERMINAL_ID = -1;
+const int Ver4DictConstants::PROBABILITY_SIZE = 1;
+const int Ver4DictConstants::FLAGS_IN_PROBABILITY_FILE_SIZE = 1;
+const int Ver4DictConstants::TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE = 3;
+const int Ver4DictConstants::NOT_A_TERMINAL_ADDRESS = 0;
+const int Ver4DictConstants::TERMINAL_ID_FIELD_SIZE = 4;
+const int Ver4DictConstants::TIME_STAMP_FIELD_SIZE = 4;
+const int Ver4DictConstants::WORD_LEVEL_FIELD_SIZE = 1;
+const int Ver4DictConstants::WORD_COUNT_FIELD_SIZE = 1;
+
+const int Ver4DictConstants::BIGRAM_ADDRESS_TABLE_BLOCK_SIZE = 16;
+const int Ver4DictConstants::BIGRAM_ADDRESS_TABLE_DATA_SIZE = 4;
+const int Ver4DictConstants::SHORTCUT_ADDRESS_TABLE_BLOCK_SIZE = 64;
+const int Ver4DictConstants::SHORTCUT_ADDRESS_TABLE_DATA_SIZE = 4;
+
+const int Ver4DictConstants::BIGRAM_TARGET_TERMINAL_ID_FIELD_SIZE = 3;
+// Unsigned int max value of BIGRAM_TARGET_TERMINAL_ID_FIELD_SIZE-byte is used for representing
+// invalid terminal ID in bigram lists.
+const int Ver4DictConstants::INVALID_BIGRAM_TARGET_TERMINAL_ID =
+        (1 << (BIGRAM_TARGET_TERMINAL_ID_FIELD_SIZE * 8)) - 1;
+const int Ver4DictConstants::BIGRAM_FLAGS_FIELD_SIZE = 1;
+const int Ver4DictConstants::BIGRAM_PROBABILITY_MASK = 0x0F;
+const int Ver4DictConstants::BIGRAM_HAS_NEXT_MASK = 0x80;
+const int Ver4DictConstants::BIGRAM_LARGE_PROBABILITY_FIELD_SIZE = 1;
+
+const int Ver4DictConstants::SHORTCUT_FLAGS_FIELD_SIZE = 1;
+const int Ver4DictConstants::SHORTCUT_PROBABILITY_MASK = 0x0F;
+const int Ver4DictConstants::SHORTCUT_HAS_NEXT_MASK = 0x80;
+
+} // namespace v401
+} // namespace backward
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h
new file mode 100644
index 0000000..17afeb1
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_VER4_DICT_CONSTANTS_H
+#define LATINIME_BACKWARD_V401_VER4_DICT_CONSTANTS_H
+
+#include "defines.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+// TODO: Create PtConstants under the pt_common and move some constant values there.
+// Note that there are corresponding definitions in FormatSpec.java.
+class Ver4DictConstants {
+ public:
+    static const char *const TRIE_FILE_EXTENSION;
+    static const char *const HEADER_FILE_EXTENSION;
+    static const char *const FREQ_FILE_EXTENSION;
+    static const char *const TERMINAL_ADDRESS_TABLE_FILE_EXTENSION;
+    static const char *const BIGRAM_FILE_EXTENSION;
+    static const char *const BIGRAM_LOOKUP_TABLE_FILE_EXTENSION;
+    static const char *const BIGRAM_CONTENT_TABLE_FILE_EXTENSION;
+    static const char *const SHORTCUT_FILE_EXTENSION;
+    static const char *const SHORTCUT_LOOKUP_TABLE_FILE_EXTENSION;
+    static const char *const SHORTCUT_CONTENT_TABLE_FILE_EXTENSION;
+
+    static const int MAX_DICTIONARY_SIZE;
+    static const int MAX_DICT_EXTENDED_REGION_SIZE;
+
+    static const int NOT_A_TERMINAL_ID;
+    static const int PROBABILITY_SIZE;
+    static const int FLAGS_IN_PROBABILITY_FILE_SIZE;
+    static const int TERMINAL_ADDRESS_TABLE_ADDRESS_SIZE;
+    static const int NOT_A_TERMINAL_ADDRESS;
+    static const int TERMINAL_ID_FIELD_SIZE;
+    static const int TIME_STAMP_FIELD_SIZE;
+    static const int WORD_LEVEL_FIELD_SIZE;
+    static const int WORD_COUNT_FIELD_SIZE;
+
+    static const int BIGRAM_ADDRESS_TABLE_BLOCK_SIZE;
+    static const int BIGRAM_ADDRESS_TABLE_DATA_SIZE;
+    static const int SHORTCUT_ADDRESS_TABLE_BLOCK_SIZE;
+    static const int SHORTCUT_ADDRESS_TABLE_DATA_SIZE;
+
+    static const int BIGRAM_FLAGS_FIELD_SIZE;
+    static const int BIGRAM_TARGET_TERMINAL_ID_FIELD_SIZE;
+    static const int INVALID_BIGRAM_TARGET_TERMINAL_ID;
+    static const int BIGRAM_PROBABILITY_MASK;
+    static const int BIGRAM_HAS_NEXT_MASK;
+    // Used when bigram list has time stamp.
+    static const int BIGRAM_LARGE_PROBABILITY_FIELD_SIZE;
+
+    static const int SHORTCUT_FLAGS_FIELD_SIZE;
+    static const int SHORTCUT_PROBABILITY_MASK;
+    static const int SHORTCUT_HAS_NEXT_MASK;
+
+ private:
+    DISALLOW_IMPLICIT_CONSTRUCTORS(Ver4DictConstants);
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_VER4_DICT_CONSTANTS_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_reader.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_reader.cpp
new file mode 100644
index 0000000..80b51b2
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_reader.cpp
@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.cpp
+ */
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_reader.h"
+
+#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/probability_dict_content.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/probability_entry.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_reading_utils.h"
+#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+const PtNodeParams Ver4PatriciaTrieNodeReader::fetchPtNodeInfoFromBufferAndProcessMovedPtNode(
+        const int ptNodePos, const int siblingNodePos) const {
+    if (ptNodePos < 0 || ptNodePos >= mBuffer->getTailPosition()) {
+        // Reading invalid position because of bug or broken dictionary.
+        AKLOGE("Fetching PtNode info from invalid dictionary position: %d, dictionary size: %d",
+                ptNodePos, mBuffer->getTailPosition());
+        ASSERT(false);
+        return PtNodeParams();
+    }
+    const bool usesAdditionalBuffer = mBuffer->isInAdditionalBuffer(ptNodePos);
+    const uint8_t *const dictBuf = mBuffer->getBuffer(usesAdditionalBuffer);
+    int pos = ptNodePos;
+    const int headPos = ptNodePos;
+    if (usesAdditionalBuffer) {
+        pos -= mBuffer->getOriginalBufferSize();
+    }
+    const PatriciaTrieReadingUtils::NodeFlags flags =
+            PatriciaTrieReadingUtils::getFlagsAndAdvancePosition(dictBuf, &pos);
+    const int parentPosOffset =
+            DynamicPtReadingUtils::getParentPtNodePosOffsetAndAdvancePosition(
+                    dictBuf, &pos);
+    const int parentPos =
+            DynamicPtReadingUtils::getParentPtNodePos(parentPosOffset, headPos);
+    int codePoints[MAX_WORD_LENGTH];
+    const int codePonitCount = PatriciaTrieReadingUtils::getCharsAndAdvancePosition(
+            dictBuf, flags, MAX_WORD_LENGTH, codePoints, &pos);
+    int terminalIdFieldPos = NOT_A_DICT_POS;
+    int terminalId = Ver4DictConstants::NOT_A_TERMINAL_ID;
+    int probability = NOT_A_PROBABILITY;
+    if (PatriciaTrieReadingUtils::isTerminal(flags)) {
+        terminalIdFieldPos = pos;
+        if (usesAdditionalBuffer) {
+            terminalIdFieldPos += mBuffer->getOriginalBufferSize();
+        }
+        terminalId = Ver4PatriciaTrieReadingUtils::getTerminalIdAndAdvancePosition(dictBuf, &pos);
+        const ProbabilityEntry probabilityEntry =
+                mProbabilityDictContent->getProbabilityEntry(terminalId);
+        if (probabilityEntry.hasHistoricalInfo()) {
+            probability = ForgettingCurveUtils::decodeProbability(
+                    probabilityEntry.getHistoricalInfo(), mHeaderPolicy);
+        } else {
+            probability = probabilityEntry.getProbability();
+        }
+    }
+    int childrenPosFieldPos = pos;
+    if (usesAdditionalBuffer) {
+        childrenPosFieldPos += mBuffer->getOriginalBufferSize();
+    }
+    int childrenPos = DynamicPtReadingUtils::readChildrenPositionAndAdvancePosition(
+            dictBuf, &pos);
+    if (usesAdditionalBuffer && childrenPos != NOT_A_DICT_POS) {
+        childrenPos += mBuffer->getOriginalBufferSize();
+    }
+    if (usesAdditionalBuffer) {
+        pos += mBuffer->getOriginalBufferSize();
+    }
+    // Sibling position is the tail position of original PtNode.
+    int newSiblingNodePos = (siblingNodePos == NOT_A_DICT_POS) ? pos : siblingNodePos;
+    // Read destination node if the read node is a moved node.
+    if (DynamicPtReadingUtils::isMoved(flags)) {
+        // The destination position is stored at the same place as the parent position.
+        return fetchPtNodeInfoFromBufferAndProcessMovedPtNode(parentPos, newSiblingNodePos);
+    } else {
+        return PtNodeParams(headPos, flags, parentPos, codePonitCount, codePoints,
+                terminalIdFieldPos, terminalId, probability, childrenPosFieldPos, childrenPos,
+                newSiblingNodePos);
+    }
+}
+
+} // namespace v401
+} // namespace backward
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_reader.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_reader.h
new file mode 100644
index 0000000..0531b0a
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_reader.h
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_reader.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_NODE_READER_H
+#define LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_NODE_READER_H
+
+#include "defines.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_reader.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+} // namespace v401
+} // namespace backward
+class BufferWithExtendableBuffer;
+namespace backward {
+namespace v401 {
+} // namespace v401
+} // namespace backward
+class HeaderPolicy;
+namespace backward {
+namespace v401 {
+class ProbabilityDictContent;
+
+/*
+ * This class is used for helping to read nodes of ver4 patricia trie. This class handles moved
+ * node and reads node attributes including probability form probabilityBuffer.
+ */
+class Ver4PatriciaTrieNodeReader : public PtNodeReader {
+ public:
+    Ver4PatriciaTrieNodeReader(const BufferWithExtendableBuffer *const buffer,
+            const ProbabilityDictContent *const probabilityDictContent,
+            const HeaderPolicy *const headerPolicy)
+            : mBuffer(buffer), mProbabilityDictContent(probabilityDictContent),
+              mHeaderPolicy(headerPolicy) {}
+
+    ~Ver4PatriciaTrieNodeReader() {}
+
+    virtual const PtNodeParams fetchNodeInfoInBufferFromPtNodePos(const int ptNodePos) const {
+        return fetchPtNodeInfoFromBufferAndProcessMovedPtNode(ptNodePos,
+                NOT_A_DICT_POS /* siblingNodePos */);
+    }
+
+ private:
+    DISALLOW_COPY_AND_ASSIGN(Ver4PatriciaTrieNodeReader);
+
+    const BufferWithExtendableBuffer *const mBuffer;
+    const ProbabilityDictContent *const mProbabilityDictContent;
+    const HeaderPolicy *const mHeaderPolicy;
+
+    const PtNodeParams fetchPtNodeInfoFromBufferAndProcessMovedPtNode(const int ptNodePos,
+            const int siblingNodePos) const;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_NODE_READER_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_writer.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_writer.cpp
new file mode 100644
index 0000000..8de6bac
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_writer.cpp
@@ -0,0 +1,429 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.cpp
+ */
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_writer.h"
+
+#include "suggest/core/dictionary/property/unigram_property.h"
+#include "suggest/policyimpl/dictionary/header/header_policy.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/bigram/ver4_bigram_list_policy.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/probability_entry.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/shortcut/ver4_shortcut_list_policy.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_reader.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_buffers.h"
+#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+const int Ver4PatriciaTrieNodeWriter::CHILDREN_POSITION_FIELD_SIZE = 3;
+
+bool Ver4PatriciaTrieNodeWriter::markPtNodeAsDeleted(
+        const PtNodeParams *const toBeUpdatedPtNodeParams) {
+    int pos = toBeUpdatedPtNodeParams->getHeadPos();
+    const bool usesAdditionalBuffer = mTrieBuffer->isInAdditionalBuffer(pos);
+    const uint8_t *const dictBuf = mTrieBuffer->getBuffer(usesAdditionalBuffer);
+    if (usesAdditionalBuffer) {
+        pos -= mTrieBuffer->getOriginalBufferSize();
+    }
+    // Read original flags
+    const PatriciaTrieReadingUtils::NodeFlags originalFlags =
+            PatriciaTrieReadingUtils::getFlagsAndAdvancePosition(dictBuf, &pos);
+    const PatriciaTrieReadingUtils::NodeFlags updatedFlags =
+            DynamicPtReadingUtils::updateAndGetFlags(originalFlags, false /* isMoved */,
+                    true /* isDeleted */, false /* willBecomeNonTerminal */);
+    int writingPos = toBeUpdatedPtNodeParams->getHeadPos();
+    // Update flags.
+    if (!DynamicPtWritingUtils::writeFlagsAndAdvancePosition(mTrieBuffer, updatedFlags,
+            &writingPos)) {
+        return false;
+    }
+    if (toBeUpdatedPtNodeParams->isTerminal()) {
+        // The PtNode is a terminal. Delete entry from the terminal position lookup table.
+        return mBuffers->getMutableTerminalPositionLookupTable()->setTerminalPtNodePosition(
+                toBeUpdatedPtNodeParams->getTerminalId(), NOT_A_DICT_POS /* ptNodePos */);
+    } else {
+        return true;
+    }
+}
+
+bool Ver4PatriciaTrieNodeWriter::markPtNodeAsMoved(
+        const PtNodeParams *const toBeUpdatedPtNodeParams,
+        const int movedPos, const int bigramLinkedNodePos) {
+    int pos = toBeUpdatedPtNodeParams->getHeadPos();
+    const bool usesAdditionalBuffer = mTrieBuffer->isInAdditionalBuffer(pos);
+    const uint8_t *const dictBuf = mTrieBuffer->getBuffer(usesAdditionalBuffer);
+    if (usesAdditionalBuffer) {
+        pos -= mTrieBuffer->getOriginalBufferSize();
+    }
+    // Read original flags
+    const PatriciaTrieReadingUtils::NodeFlags originalFlags =
+            PatriciaTrieReadingUtils::getFlagsAndAdvancePosition(dictBuf, &pos);
+    const PatriciaTrieReadingUtils::NodeFlags updatedFlags =
+            DynamicPtReadingUtils::updateAndGetFlags(originalFlags, true /* isMoved */,
+                    false /* isDeleted */, false /* willBecomeNonTerminal */);
+    int writingPos = toBeUpdatedPtNodeParams->getHeadPos();
+    // Update flags.
+    if (!DynamicPtWritingUtils::writeFlagsAndAdvancePosition(mTrieBuffer, updatedFlags,
+            &writingPos)) {
+        return false;
+    }
+    // Update moved position, which is stored in the parent offset field.
+    if (!DynamicPtWritingUtils::writeParentPosOffsetAndAdvancePosition(
+            mTrieBuffer, movedPos, toBeUpdatedPtNodeParams->getHeadPos(), &writingPos)) {
+        return false;
+    }
+    if (toBeUpdatedPtNodeParams->hasChildren()) {
+        // Update children's parent position.
+        mReadingHelper.initWithPtNodeArrayPos(toBeUpdatedPtNodeParams->getChildrenPos());
+        while (!mReadingHelper.isEnd()) {
+            const PtNodeParams childPtNodeParams(mReadingHelper.getPtNodeParams());
+            int parentOffsetFieldPos = childPtNodeParams.getHeadPos()
+                    + DynamicPtWritingUtils::NODE_FLAG_FIELD_SIZE;
+            if (!DynamicPtWritingUtils::writeParentPosOffsetAndAdvancePosition(
+                    mTrieBuffer, bigramLinkedNodePos, childPtNodeParams.getHeadPos(),
+                    &parentOffsetFieldPos)) {
+                // Parent offset cannot be written because of a bug or a broken dictionary; thus,
+                // we give up to update dictionary.
+                return false;
+            }
+            mReadingHelper.readNextSiblingNode(childPtNodeParams);
+        }
+    }
+    return true;
+}
+
+bool Ver4PatriciaTrieNodeWriter::markPtNodeAsWillBecomeNonTerminal(
+        const PtNodeParams *const toBeUpdatedPtNodeParams) {
+    int pos = toBeUpdatedPtNodeParams->getHeadPos();
+    const bool usesAdditionalBuffer = mTrieBuffer->isInAdditionalBuffer(pos);
+    const uint8_t *const dictBuf = mTrieBuffer->getBuffer(usesAdditionalBuffer);
+    if (usesAdditionalBuffer) {
+        pos -= mTrieBuffer->getOriginalBufferSize();
+    }
+    // Read original flags
+    const PatriciaTrieReadingUtils::NodeFlags originalFlags =
+            PatriciaTrieReadingUtils::getFlagsAndAdvancePosition(dictBuf, &pos);
+    const PatriciaTrieReadingUtils::NodeFlags updatedFlags =
+            DynamicPtReadingUtils::updateAndGetFlags(originalFlags, false /* isMoved */,
+                    false /* isDeleted */, true /* willBecomeNonTerminal */);
+    if (!mBuffers->getMutableTerminalPositionLookupTable()->setTerminalPtNodePosition(
+            toBeUpdatedPtNodeParams->getTerminalId(), NOT_A_DICT_POS /* ptNodePos */)) {
+        AKLOGE("Cannot update terminal position lookup table. terminal id: %d",
+                toBeUpdatedPtNodeParams->getTerminalId());
+        return false;
+    }
+    // Update flags.
+    int writingPos = toBeUpdatedPtNodeParams->getHeadPos();
+    return DynamicPtWritingUtils::writeFlagsAndAdvancePosition(mTrieBuffer, updatedFlags,
+            &writingPos);
+}
+
+bool Ver4PatriciaTrieNodeWriter::updatePtNodeUnigramProperty(
+        const PtNodeParams *const toBeUpdatedPtNodeParams,
+        const UnigramProperty *const unigramProperty) {
+    // Update probability and historical information.
+    // TODO: Update other information in the unigram property.
+    if (!toBeUpdatedPtNodeParams->isTerminal()) {
+        return false;
+    }
+    const ProbabilityEntry originalProbabilityEntry =
+            mBuffers->getProbabilityDictContent()->getProbabilityEntry(
+                    toBeUpdatedPtNodeParams->getTerminalId());
+    const ProbabilityEntry probabilityEntry = createUpdatedEntryFrom(&originalProbabilityEntry,
+            unigramProperty);
+    return mBuffers->getMutableProbabilityDictContent()->setProbabilityEntry(
+            toBeUpdatedPtNodeParams->getTerminalId(), &probabilityEntry);
+}
+
+bool Ver4PatriciaTrieNodeWriter::updatePtNodeProbabilityAndGetNeedsToKeepPtNodeAfterGC(
+        const PtNodeParams *const toBeUpdatedPtNodeParams, bool *const outNeedsToKeepPtNode) {
+    if (!toBeUpdatedPtNodeParams->isTerminal()) {
+        AKLOGE("updatePtNodeProbabilityAndGetNeedsToSaveForGC is called for non-terminal PtNode.");
+        return false;
+    }
+    const ProbabilityEntry originalProbabilityEntry =
+            mBuffers->getProbabilityDictContent()->getProbabilityEntry(
+                    toBeUpdatedPtNodeParams->getTerminalId());
+    if (originalProbabilityEntry.hasHistoricalInfo()) {
+        const HistoricalInfo historicalInfo = ForgettingCurveUtils::createHistoricalInfoToSave(
+                originalProbabilityEntry.getHistoricalInfo(), mHeaderPolicy);
+        const ProbabilityEntry probabilityEntry =
+                originalProbabilityEntry.createEntryWithUpdatedHistoricalInfo(&historicalInfo);
+        if (!mBuffers->getMutableProbabilityDictContent()->setProbabilityEntry(
+                toBeUpdatedPtNodeParams->getTerminalId(), &probabilityEntry)) {
+            AKLOGE("Cannot write updated probability entry. terminalId: %d",
+                    toBeUpdatedPtNodeParams->getTerminalId());
+            return false;
+        }
+        const bool isValid = ForgettingCurveUtils::needsToKeep(&historicalInfo, mHeaderPolicy);
+        if (!isValid) {
+            if (!markPtNodeAsWillBecomeNonTerminal(toBeUpdatedPtNodeParams)) {
+                AKLOGE("Cannot mark PtNode as willBecomeNonTerminal.");
+                return false;
+            }
+        }
+        *outNeedsToKeepPtNode = isValid;
+    } else {
+        // No need to update probability.
+        *outNeedsToKeepPtNode = true;
+    }
+    return true;
+}
+
+bool Ver4PatriciaTrieNodeWriter::updateChildrenPosition(
+        const PtNodeParams *const toBeUpdatedPtNodeParams, const int newChildrenPosition) {
+    int childrenPosFieldPos = toBeUpdatedPtNodeParams->getChildrenPosFieldPos();
+    return DynamicPtWritingUtils::writeChildrenPositionAndAdvancePosition(mTrieBuffer,
+            newChildrenPosition, &childrenPosFieldPos);
+}
+
+bool Ver4PatriciaTrieNodeWriter::updateTerminalId(const PtNodeParams *const toBeUpdatedPtNodeParams,
+        const int newTerminalId) {
+    return mTrieBuffer->writeUint(newTerminalId, Ver4DictConstants::TERMINAL_ID_FIELD_SIZE,
+            toBeUpdatedPtNodeParams->getTerminalIdFieldPos());
+}
+
+bool Ver4PatriciaTrieNodeWriter::writePtNodeAndAdvancePosition(
+        const PtNodeParams *const ptNodeParams, int *const ptNodeWritingPos) {
+    return writePtNodeAndGetTerminalIdAndAdvancePosition(ptNodeParams, 0 /* outTerminalId */,
+            ptNodeWritingPos);
+}
+
+
+bool Ver4PatriciaTrieNodeWriter::writeNewTerminalPtNodeAndAdvancePosition(
+        const PtNodeParams *const ptNodeParams, const UnigramProperty *const unigramProperty,
+        int *const ptNodeWritingPos) {
+    int terminalId = Ver4DictConstants::NOT_A_TERMINAL_ID;
+    if (!writePtNodeAndGetTerminalIdAndAdvancePosition(ptNodeParams, &terminalId,
+            ptNodeWritingPos)) {
+        return false;
+    }
+    // Write probability.
+    ProbabilityEntry newProbabilityEntry;
+    const ProbabilityEntry probabilityEntryToWrite = createUpdatedEntryFrom(
+            &newProbabilityEntry, unigramProperty);
+    return mBuffers->getMutableProbabilityDictContent()->setProbabilityEntry(terminalId,
+            &probabilityEntryToWrite);
+}
+
+bool Ver4PatriciaTrieNodeWriter::addNewBigramEntry(
+        const PtNodeParams *const sourcePtNodeParams, const PtNodeParams *const targetPtNodeParam,
+        const BigramProperty *const bigramProperty, bool *const outAddedNewBigram) {
+    if (!mBigramPolicy->addNewEntry(sourcePtNodeParams->getTerminalId(),
+            targetPtNodeParam->getTerminalId(), bigramProperty, outAddedNewBigram)) {
+        AKLOGE("Cannot add new bigram entry. terminalId: %d, targetTerminalId: %d",
+                sourcePtNodeParams->getTerminalId(), targetPtNodeParam->getTerminalId());
+        return false;
+    }
+    if (!sourcePtNodeParams->hasBigrams()) {
+        // Update has bigrams flag.
+        return updatePtNodeFlags(sourcePtNodeParams->getHeadPos(),
+                sourcePtNodeParams->isBlacklisted(), sourcePtNodeParams->isNotAWord(),
+                sourcePtNodeParams->isTerminal(), sourcePtNodeParams->hasShortcutTargets(),
+                true /* hasBigrams */,
+                sourcePtNodeParams->getCodePointCount() > 1 /* hasMultipleChars */);
+    }
+    return true;
+}
+
+bool Ver4PatriciaTrieNodeWriter::removeBigramEntry(
+        const PtNodeParams *const sourcePtNodeParams, const PtNodeParams *const targetPtNodeParam) {
+    return mBigramPolicy->removeEntry(sourcePtNodeParams->getTerminalId(),
+            targetPtNodeParam->getTerminalId());
+}
+
+bool Ver4PatriciaTrieNodeWriter::updateAllBigramEntriesAndDeleteUselessEntries(
+            const PtNodeParams *const sourcePtNodeParams, int *const outBigramEntryCount) {
+    return mBigramPolicy->updateAllBigramEntriesAndDeleteUselessEntries(
+            sourcePtNodeParams->getTerminalId(), outBigramEntryCount);
+}
+
+bool Ver4PatriciaTrieNodeWriter::updateAllPositionFields(
+        const PtNodeParams *const toBeUpdatedPtNodeParams,
+        const DictPositionRelocationMap *const dictPositionRelocationMap,
+        int *const outBigramEntryCount) {
+    int parentPos = toBeUpdatedPtNodeParams->getParentPos();
+    if (parentPos != NOT_A_DICT_POS) {
+        PtNodeWriter::PtNodePositionRelocationMap::const_iterator it =
+                dictPositionRelocationMap->mPtNodePositionRelocationMap.find(parentPos);
+        if (it != dictPositionRelocationMap->mPtNodePositionRelocationMap.end()) {
+            parentPos = it->second;
+        }
+    }
+    int writingPos = toBeUpdatedPtNodeParams->getHeadPos()
+            + DynamicPtWritingUtils::NODE_FLAG_FIELD_SIZE;
+    // Write updated parent offset.
+    if (!DynamicPtWritingUtils::writeParentPosOffsetAndAdvancePosition(mTrieBuffer,
+            parentPos, toBeUpdatedPtNodeParams->getHeadPos(), &writingPos)) {
+        return false;
+    }
+
+    // Updates children position.
+    int childrenPos = toBeUpdatedPtNodeParams->getChildrenPos();
+    if (childrenPos != NOT_A_DICT_POS) {
+        PtNodeWriter::PtNodeArrayPositionRelocationMap::const_iterator it =
+                dictPositionRelocationMap->mPtNodeArrayPositionRelocationMap.find(childrenPos);
+        if (it != dictPositionRelocationMap->mPtNodeArrayPositionRelocationMap.end()) {
+            childrenPos = it->second;
+        }
+    }
+    if (!updateChildrenPosition(toBeUpdatedPtNodeParams, childrenPos)) {
+        return false;
+    }
+
+    // Counts bigram entries.
+    if (outBigramEntryCount) {
+        *outBigramEntryCount = mBigramPolicy->getBigramEntryConut(
+                toBeUpdatedPtNodeParams->getTerminalId());
+    }
+    return true;
+}
+
+bool Ver4PatriciaTrieNodeWriter::addShortcutTarget(const PtNodeParams *const ptNodeParams,
+        const int *const targetCodePoints, const int targetCodePointCount,
+        const int shortcutProbability) {
+    if (!mShortcutPolicy->addNewShortcut(ptNodeParams->getTerminalId(),
+            targetCodePoints, targetCodePointCount, shortcutProbability)) {
+        AKLOGE("Cannot add new shortuct entry. terminalId: %d", ptNodeParams->getTerminalId());
+        return false;
+    }
+    if (!ptNodeParams->hasShortcutTargets()) {
+        // Update has shortcut targets flag.
+        return updatePtNodeFlags(ptNodeParams->getHeadPos(),
+                ptNodeParams->isBlacklisted(), ptNodeParams->isNotAWord(),
+                ptNodeParams->isTerminal(), true /* hasShortcutTargets */,
+                ptNodeParams->hasBigrams(),
+                ptNodeParams->getCodePointCount() > 1 /* hasMultipleChars */);
+    }
+    return true;
+}
+
+bool Ver4PatriciaTrieNodeWriter::updatePtNodeHasBigramsAndShortcutTargetsFlags(
+        const PtNodeParams *const ptNodeParams) {
+    const bool hasBigrams = mBuffers->getBigramDictContent()->getBigramListHeadPos(
+            ptNodeParams->getTerminalId()) != NOT_A_DICT_POS;
+    const bool hasShortcutTargets = mBuffers->getShortcutDictContent()->getShortcutListHeadPos(
+            ptNodeParams->getTerminalId()) != NOT_A_DICT_POS;
+    return updatePtNodeFlags(ptNodeParams->getHeadPos(), ptNodeParams->isBlacklisted(),
+            ptNodeParams->isNotAWord(), ptNodeParams->isTerminal(), hasShortcutTargets,
+            hasBigrams, ptNodeParams->getCodePointCount() > 1 /* hasMultipleChars */);
+}
+
+bool Ver4PatriciaTrieNodeWriter::writePtNodeAndGetTerminalIdAndAdvancePosition(
+        const PtNodeParams *const ptNodeParams, int *const outTerminalId,
+        int *const ptNodeWritingPos) {
+    const int nodePos = *ptNodeWritingPos;
+    // Write dummy flags. The Node flags are updated with appropriate flags at the last step of the
+    // PtNode writing.
+    if (!DynamicPtWritingUtils::writeFlagsAndAdvancePosition(mTrieBuffer,
+            0 /* nodeFlags */, ptNodeWritingPos)) {
+        return false;
+    }
+    // Calculate a parent offset and write the offset.
+    if (!DynamicPtWritingUtils::writeParentPosOffsetAndAdvancePosition(mTrieBuffer,
+            ptNodeParams->getParentPos(), nodePos, ptNodeWritingPos)) {
+        return false;
+    }
+    // Write code points
+    if (!DynamicPtWritingUtils::writeCodePointsAndAdvancePosition(mTrieBuffer,
+            ptNodeParams->getCodePoints(), ptNodeParams->getCodePointCount(), ptNodeWritingPos)) {
+        return false;
+    }
+    int terminalId = Ver4DictConstants::NOT_A_TERMINAL_ID;
+    if (!ptNodeParams->willBecomeNonTerminal()) {
+        if (ptNodeParams->getTerminalId() != Ver4DictConstants::NOT_A_TERMINAL_ID) {
+            terminalId = ptNodeParams->getTerminalId();
+        } else if (ptNodeParams->isTerminal()) {
+            // Write terminal information using a new terminal id.
+            // Get a new unused terminal id.
+            terminalId = mBuffers->getTerminalPositionLookupTable()->getNextTerminalId();
+        }
+    }
+    const int isTerminal = terminalId != Ver4DictConstants::NOT_A_TERMINAL_ID;
+    if (isTerminal) {
+        // Update the lookup table.
+        if (!mBuffers->getMutableTerminalPositionLookupTable()->setTerminalPtNodePosition(
+                terminalId, nodePos)) {
+            return false;
+        }
+        // Write terminal Id.
+        if (!mTrieBuffer->writeUintAndAdvancePosition(terminalId,
+                Ver4DictConstants::TERMINAL_ID_FIELD_SIZE, ptNodeWritingPos)) {
+            return false;
+        }
+        if (outTerminalId) {
+            *outTerminalId = terminalId;
+        }
+    }
+    // Write children position
+    if (!DynamicPtWritingUtils::writeChildrenPositionAndAdvancePosition(mTrieBuffer,
+            ptNodeParams->getChildrenPos(), ptNodeWritingPos)) {
+        return false;
+    }
+    return updatePtNodeFlags(nodePos, ptNodeParams->isBlacklisted(), ptNodeParams->isNotAWord(),
+            isTerminal, ptNodeParams->hasShortcutTargets(), ptNodeParams->hasBigrams(),
+            ptNodeParams->getCodePointCount() > 1 /* hasMultipleChars */);
+}
+
+const ProbabilityEntry Ver4PatriciaTrieNodeWriter::createUpdatedEntryFrom(
+        const ProbabilityEntry *const originalProbabilityEntry,
+        const UnigramProperty *const unigramProperty) const {
+    // TODO: Consolidate historical info and probability.
+    if (mHeaderPolicy->hasHistoricalInfoOfWords()) {
+        const HistoricalInfo historicalInfoForUpdate(unigramProperty->getTimestamp(),
+                unigramProperty->getLevel(), unigramProperty->getCount());
+        const HistoricalInfo updatedHistoricalInfo =
+                ForgettingCurveUtils::createUpdatedHistoricalInfo(
+                        originalProbabilityEntry->getHistoricalInfo(),
+                        unigramProperty->getProbability(), &historicalInfoForUpdate, mHeaderPolicy);
+        return originalProbabilityEntry->createEntryWithUpdatedHistoricalInfo(
+                &updatedHistoricalInfo);
+    } else {
+        return originalProbabilityEntry->createEntryWithUpdatedProbability(
+                unigramProperty->getProbability());
+    }
+}
+
+bool Ver4PatriciaTrieNodeWriter::updatePtNodeFlags(const int ptNodePos,
+        const bool isBlacklisted, const bool isNotAWord, const bool isTerminal,
+        const bool hasShortcutTargets, const bool hasBigrams, const bool hasMultipleChars) {
+    // Create node flags and write them.
+    PatriciaTrieReadingUtils::NodeFlags nodeFlags =
+            PatriciaTrieReadingUtils::createAndGetFlags(isBlacklisted, isNotAWord, isTerminal,
+                    hasShortcutTargets, hasBigrams, hasMultipleChars,
+                    CHILDREN_POSITION_FIELD_SIZE);
+    if (!DynamicPtWritingUtils::writeFlags(mTrieBuffer, nodeFlags, ptNodePos)) {
+        AKLOGE("Cannot write PtNode flags. flags: %x, pos: %d", nodeFlags, ptNodePos);
+        return false;
+    }
+    return true;
+}
+
+} // namespace v401
+} // namespace backward
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_writer.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_writer.h
new file mode 100644
index 0000000..7f1851d
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_writer.h
@@ -0,0 +1,145 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_node_writer.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_NODE_WRITER_H
+#define LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_NODE_WRITER_H
+
+#include "defines.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_writer.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/probability_entry.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+} // namespace v401
+} // namespace backward
+class BufferWithExtendableBuffer;
+namespace backward {
+namespace v401 {
+} // namespace v401
+} // namespace backward
+class HeaderPolicy;
+namespace backward {
+namespace v401 {
+class Ver4BigramListPolicy;
+class Ver4DictBuffers;
+class Ver4PatriciaTrieNodeReader;
+class Ver4PtNodeArrayReader;
+class Ver4ShortcutListPolicy;
+
+/*
+ * This class is used for helping to writes nodes of ver4 patricia trie.
+ */
+class Ver4PatriciaTrieNodeWriter : public PtNodeWriter {
+ public:
+    Ver4PatriciaTrieNodeWriter(BufferWithExtendableBuffer *const trieBuffer,
+            Ver4DictBuffers *const buffers, const HeaderPolicy *const headerPolicy,
+            const PtNodeReader *const ptNodeReader,
+            const PtNodeArrayReader *const ptNodeArrayReader,
+            Ver4BigramListPolicy *const bigramPolicy, Ver4ShortcutListPolicy *const shortcutPolicy)
+            : mTrieBuffer(trieBuffer), mBuffers(buffers), mHeaderPolicy(headerPolicy),
+              mReadingHelper(ptNodeReader, ptNodeArrayReader), mBigramPolicy(bigramPolicy),
+              mShortcutPolicy(shortcutPolicy) {}
+
+    virtual ~Ver4PatriciaTrieNodeWriter() {}
+
+    virtual bool markPtNodeAsDeleted(const PtNodeParams *const toBeUpdatedPtNodeParams);
+
+    virtual bool markPtNodeAsMoved(const PtNodeParams *const toBeUpdatedPtNodeParams,
+            const int movedPos, const int bigramLinkedNodePos);
+
+    virtual bool markPtNodeAsWillBecomeNonTerminal(
+            const PtNodeParams *const toBeUpdatedPtNodeParams);
+
+    virtual bool updatePtNodeUnigramProperty(const PtNodeParams *const toBeUpdatedPtNodeParams,
+            const UnigramProperty *const unigramProperty);
+
+    virtual bool updatePtNodeProbabilityAndGetNeedsToKeepPtNodeAfterGC(
+            const PtNodeParams *const toBeUpdatedPtNodeParams, bool *const outNeedsToKeepPtNode);
+
+    virtual bool updateChildrenPosition(const PtNodeParams *const toBeUpdatedPtNodeParams,
+            const int newChildrenPosition);
+
+    bool updateTerminalId(const PtNodeParams *const toBeUpdatedPtNodeParams,
+            const int newTerminalId);
+
+    virtual bool writePtNodeAndAdvancePosition(const PtNodeParams *const ptNodeParams,
+            int *const ptNodeWritingPos);
+
+    virtual bool writeNewTerminalPtNodeAndAdvancePosition(const PtNodeParams *const ptNodeParams,
+            const UnigramProperty *const unigramProperty, int *const ptNodeWritingPos);
+
+    virtual bool addNewBigramEntry(const PtNodeParams *const sourcePtNodeParams,
+            const PtNodeParams *const targetPtNodeParam, const BigramProperty *const bigramProperty,
+            bool *const outAddedNewBigram);
+
+    virtual bool removeBigramEntry(const PtNodeParams *const sourcePtNodeParams,
+            const PtNodeParams *const targetPtNodeParam);
+
+    virtual bool updateAllBigramEntriesAndDeleteUselessEntries(
+            const PtNodeParams *const sourcePtNodeParams, int *const outBigramEntryCount);
+
+    virtual bool updateAllPositionFields(const PtNodeParams *const toBeUpdatedPtNodeParams,
+            const DictPositionRelocationMap *const dictPositionRelocationMap,
+            int *const outBigramEntryCount);
+
+    virtual bool addShortcutTarget(const PtNodeParams *const ptNodeParams,
+            const int *const targetCodePoints, const int targetCodePointCount,
+            const int shortcutProbability);
+
+    bool updatePtNodeHasBigramsAndShortcutTargetsFlags(const PtNodeParams *const ptNodeParams);
+
+ private:
+    DISALLOW_COPY_AND_ASSIGN(Ver4PatriciaTrieNodeWriter);
+
+    bool writePtNodeAndGetTerminalIdAndAdvancePosition(
+            const PtNodeParams *const ptNodeParams, int *const outTerminalId,
+            int *const ptNodeWritingPos);
+
+    // Create updated probability entry using given unigram property. In addition to the
+    // probability, this method updates historical information if needed.
+    // TODO: Update flags belonging to the unigram property.
+    const ProbabilityEntry createUpdatedEntryFrom(
+            const ProbabilityEntry *const originalProbabilityEntry,
+            const UnigramProperty *const unigramProperty) const;
+
+    bool updatePtNodeFlags(const int ptNodePos, const bool isBlacklisted, const bool isNotAWord,
+            const bool isTerminal, const bool hasShortcutTargets, const bool hasBigrams,
+            const bool hasMultipleChars);
+
+    static const int CHILDREN_POSITION_FIELD_SIZE;
+
+    BufferWithExtendableBuffer *const mTrieBuffer;
+    Ver4DictBuffers *const mBuffers;
+    const HeaderPolicy *const mHeaderPolicy;
+    DynamicPtReadingHelper mReadingHelper;
+    Ver4BigramListPolicy *const mBigramPolicy;
+    Ver4ShortcutListPolicy *const mShortcutPolicy;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_NODE_WRITER_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_policy.cpp
new file mode 100644
index 0000000..dde1af2
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_policy.cpp
@@ -0,0 +1,475 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT CHANGE THE LOGIC IN THIS FILE !!!!!
+ * Do not edit this file other than updating policy's interface.
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
+ */
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_policy.h"
+
+#include <vector>
+
+#include "suggest/core/dicnode/dic_node.h"
+#include "suggest/core/dicnode/dic_node_vector.h"
+#include "suggest/core/dictionary/property/bigram_property.h"
+#include "suggest/core/dictionary/property/unigram_property.h"
+#include "suggest/core/dictionary/property/word_property.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_reader.h"
+#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
+#include "suggest/policyimpl/dictionary/utils/probability_utils.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+// Note that there are corresponding definitions in Java side in BinaryDictionaryTests and
+// BinaryDictionaryDecayingTests.
+const char *const Ver4PatriciaTriePolicy::UNIGRAM_COUNT_QUERY = "UNIGRAM_COUNT";
+const char *const Ver4PatriciaTriePolicy::BIGRAM_COUNT_QUERY = "BIGRAM_COUNT";
+const char *const Ver4PatriciaTriePolicy::MAX_UNIGRAM_COUNT_QUERY = "MAX_UNIGRAM_COUNT";
+const char *const Ver4PatriciaTriePolicy::MAX_BIGRAM_COUNT_QUERY = "MAX_BIGRAM_COUNT";
+const int Ver4PatriciaTriePolicy::MARGIN_TO_REFUSE_DYNAMIC_OPERATIONS = 1024;
+const int Ver4PatriciaTriePolicy::MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS =
+        Ver4DictConstants::MAX_DICTIONARY_SIZE - MARGIN_TO_REFUSE_DYNAMIC_OPERATIONS;
+
+void Ver4PatriciaTriePolicy::createAndGetAllChildDicNodes(const DicNode *const dicNode,
+        DicNodeVector *const childDicNodes) const {
+    if (!dicNode->hasChildren()) {
+        return;
+    }
+    DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
+    readingHelper.initWithPtNodeArrayPos(dicNode->getChildrenPtNodeArrayPos());
+    while (!readingHelper.isEnd()) {
+        const PtNodeParams ptNodeParams = readingHelper.getPtNodeParams();
+        if (!ptNodeParams.isValid()) {
+            break;
+        }
+        bool isTerminal = ptNodeParams.isTerminal() && !ptNodeParams.isDeleted();
+        if (isTerminal && mHeaderPolicy->isDecayingDict()) {
+            // A DecayingDict may have a terminal PtNode that has a terminal DicNode whose
+            // probability is NOT_A_PROBABILITY. In such case, we don't want to treat it as a
+            // valid terminal DicNode.
+            isTerminal = ptNodeParams.getProbability() != NOT_A_PROBABILITY;
+        }
+        childDicNodes->pushLeavingChild(dicNode, ptNodeParams.getHeadPos(),
+                ptNodeParams.getChildrenPos(), ptNodeParams.getProbability(), isTerminal,
+                ptNodeParams.hasChildren(),
+                ptNodeParams.isBlacklisted()
+                        || ptNodeParams.isNotAWord() /* isBlacklistedOrNotAWord */,
+                ptNodeParams.getCodePointCount(), ptNodeParams.getCodePoints());
+        readingHelper.readNextSiblingNode(ptNodeParams);
+    }
+    if (readingHelper.isError()) {
+        mIsCorrupted = true;
+        AKLOGE("Dictionary reading error in createAndGetAllChildDicNodes().");
+    }
+}
+
+int Ver4PatriciaTriePolicy::getCodePointsAndProbabilityAndReturnCodePointCount(
+        const int ptNodePos, const int maxCodePointCount, int *const outCodePoints,
+        int *const outUnigramProbability) const {
+    DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
+    readingHelper.initWithPtNodePos(ptNodePos);
+    const int codePointCount =  readingHelper.getCodePointsAndProbabilityAndReturnCodePointCount(
+            maxCodePointCount, outCodePoints, outUnigramProbability);
+    if (readingHelper.isError()) {
+        mIsCorrupted = true;
+        AKLOGE("Dictionary reading error in getCodePointsAndProbabilityAndReturnCodePointCount().");
+    }
+    return codePointCount;
+}
+
+int Ver4PatriciaTriePolicy::getTerminalPtNodePositionOfWord(const int *const inWord,
+        const int length, const bool forceLowerCaseSearch) const {
+    DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
+    readingHelper.initWithPtNodeArrayPos(getRootPosition());
+    const int ptNodePos =
+            readingHelper.getTerminalPtNodePositionOfWord(inWord, length, forceLowerCaseSearch);
+    if (readingHelper.isError()) {
+        mIsCorrupted = true;
+        AKLOGE("Dictionary reading error in createAndGetAllChildDicNodes().");
+    }
+    return ptNodePos;
+}
+
+int Ver4PatriciaTriePolicy::getProbability(const int unigramProbability,
+        const int bigramProbability) const {
+    if (mHeaderPolicy->isDecayingDict()) {
+        // Both probabilities are encoded. Decode them and get probability.
+        return ForgettingCurveUtils::getProbability(unigramProbability, bigramProbability);
+    } else {
+        if (unigramProbability == NOT_A_PROBABILITY) {
+            return NOT_A_PROBABILITY;
+        } else if (bigramProbability == NOT_A_PROBABILITY) {
+            return ProbabilityUtils::backoff(unigramProbability);
+        } else {
+            // bigramProbability is a bigram probability delta.
+            return ProbabilityUtils::computeProbabilityForBigram(unigramProbability,
+                    bigramProbability);
+        }
+    }
+}
+
+int Ver4PatriciaTriePolicy::getUnigramProbabilityOfPtNode(const int ptNodePos) const {
+    if (ptNodePos == NOT_A_DICT_POS) {
+        return NOT_A_PROBABILITY;
+    }
+    const PtNodeParams ptNodeParams(mNodeReader.fetchNodeInfoInBufferFromPtNodePos(ptNodePos));
+    if (ptNodeParams.isDeleted() || ptNodeParams.isBlacklisted() || ptNodeParams.isNotAWord()) {
+        return NOT_A_PROBABILITY;
+    }
+    return getProbability(ptNodeParams.getProbability(), NOT_A_PROBABILITY);
+}
+
+int Ver4PatriciaTriePolicy::getShortcutPositionOfPtNode(const int ptNodePos) const {
+    if (ptNodePos == NOT_A_DICT_POS) {
+        return NOT_A_DICT_POS;
+    }
+    const PtNodeParams ptNodeParams(mNodeReader.fetchNodeInfoInBufferFromPtNodePos(ptNodePos));
+    if (ptNodeParams.isDeleted()) {
+        return NOT_A_DICT_POS;
+    }
+    return mBuffers->getShortcutDictContent()->getShortcutListHeadPos(
+            ptNodeParams.getTerminalId());
+}
+
+int Ver4PatriciaTriePolicy::getBigramsPositionOfPtNode(const int ptNodePos) const {
+    if (ptNodePos == NOT_A_DICT_POS) {
+        return NOT_A_DICT_POS;
+    }
+    const PtNodeParams ptNodeParams(mNodeReader.fetchNodeInfoInBufferFromPtNodePos(ptNodePos));
+    if (ptNodeParams.isDeleted()) {
+        return NOT_A_DICT_POS;
+    }
+    return mBuffers->getBigramDictContent()->getBigramListHeadPos(
+            ptNodeParams.getTerminalId());
+}
+
+bool Ver4PatriciaTriePolicy::addUnigramWord(const int *const word, const int length,
+        const UnigramProperty *const unigramProperty) {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: addUnigramWord() is called for non-updatable dictionary.");
+        return false;
+    }
+    if (mDictBuffer->getTailPosition() >= MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS) {
+        AKLOGE("The dictionary is too large to dynamically update. Dictionary size: %d",
+                mDictBuffer->getTailPosition());
+        return false;
+    }
+    if (length > MAX_WORD_LENGTH) {
+        AKLOGE("The word is too long to insert to the dictionary, length: %d", length);
+        return false;
+    }
+    for (const auto &shortcut : unigramProperty->getShortcuts()) {
+        if (shortcut.getTargetCodePoints()->size() > MAX_WORD_LENGTH) {
+            AKLOGE("One of shortcut targets is too long to insert to the dictionary, length: %d",
+                    shortcut.getTargetCodePoints()->size());
+            return false;
+        }
+    }
+    DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
+    readingHelper.initWithPtNodeArrayPos(getRootPosition());
+    bool addedNewUnigram = false;
+    if (mUpdatingHelper.addUnigramWord(&readingHelper, word, length,
+            unigramProperty, &addedNewUnigram)) {
+        if (addedNewUnigram) {
+            mUnigramCount++;
+        }
+        if (unigramProperty->getShortcuts().size() > 0) {
+            // Add shortcut target.
+            const int wordPos = getTerminalPtNodePositionOfWord(word, length,
+                    false /* forceLowerCaseSearch */);
+            if (wordPos == NOT_A_DICT_POS) {
+                AKLOGE("Cannot find terminal PtNode position to add shortcut target.");
+                return false;
+            }
+            for (const auto &shortcut : unigramProperty->getShortcuts()) {
+                if (!mUpdatingHelper.addShortcutTarget(wordPos,
+                        shortcut.getTargetCodePoints()->data(),
+                        shortcut.getTargetCodePoints()->size(), shortcut.getProbability())) {
+                    AKLOGE("Cannot add new shortcut target. PtNodePos: %d, length: %d, "
+                            "probability: %d", wordPos, shortcut.getTargetCodePoints()->size(),
+                            shortcut.getProbability());
+                    return false;
+                }
+            }
+        }
+        return true;
+    } else {
+        return false;
+    }
+}
+
+bool Ver4PatriciaTriePolicy::addBigramWords(const int *const word0, const int length0,
+        const BigramProperty *const bigramProperty) {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: addBigramWords() is called for non-updatable dictionary.");
+        return false;
+    }
+    if (mDictBuffer->getTailPosition() >= MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS) {
+        AKLOGE("The dictionary is too large to dynamically update. Dictionary size: %d",
+                mDictBuffer->getTailPosition());
+        return false;
+    }
+    if (length0 > MAX_WORD_LENGTH
+            || bigramProperty->getTargetCodePoints()->size() > MAX_WORD_LENGTH) {
+        AKLOGE("Either src word or target word is too long to insert the bigram to the dictionary. "
+                "length0: %d, length1: %d", length0, bigramProperty->getTargetCodePoints()->size());
+        return false;
+    }
+    const int word0Pos = getTerminalPtNodePositionOfWord(word0, length0,
+            false /* forceLowerCaseSearch */);
+    if (word0Pos == NOT_A_DICT_POS) {
+        return false;
+    }
+    const int word1Pos = getTerminalPtNodePositionOfWord(
+            bigramProperty->getTargetCodePoints()->data(),
+            bigramProperty->getTargetCodePoints()->size(), false /* forceLowerCaseSearch */);
+    if (word1Pos == NOT_A_DICT_POS) {
+        return false;
+    }
+    bool addedNewBigram = false;
+    if (mUpdatingHelper.addBigramWords(word0Pos, word1Pos, bigramProperty, &addedNewBigram)) {
+        if (addedNewBigram) {
+            mBigramCount++;
+        }
+        return true;
+    } else {
+        return false;
+    }
+}
+
+bool Ver4PatriciaTriePolicy::removeBigramWords(const int *const word0, const int length0,
+        const int *const word1, const int length1) {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: addBigramWords() is called for non-updatable dictionary.");
+        return false;
+    }
+    if (mDictBuffer->getTailPosition() >= MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS) {
+        AKLOGE("The dictionary is too large to dynamically update. Dictionary size: %d",
+                mDictBuffer->getTailPosition());
+        return false;
+    }
+    if (length0 > MAX_WORD_LENGTH || length1 > MAX_WORD_LENGTH) {
+        AKLOGE("Either src word or target word is too long to remove the bigram to from the "
+                "dictionary. length0: %d, length1: %d", length0, length1);
+        return false;
+    }
+    const int word0Pos = getTerminalPtNodePositionOfWord(word0, length0,
+            false /* forceLowerCaseSearch */);
+    if (word0Pos == NOT_A_DICT_POS) {
+        return false;
+    }
+    const int word1Pos = getTerminalPtNodePositionOfWord(word1, length1,
+            false /* forceLowerCaseSearch */);
+    if (word1Pos == NOT_A_DICT_POS) {
+        return false;
+    }
+    if (mUpdatingHelper.removeBigramWords(word0Pos, word1Pos)) {
+        mBigramCount--;
+        return true;
+    } else {
+        return false;
+    }
+}
+
+void Ver4PatriciaTriePolicy::flush(const char *const filePath) {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: flush() is called for non-updatable dictionary. filePath: %s", filePath);
+        return;
+    }
+    if (!mWritingHelper.writeToDictFile(filePath, mUnigramCount, mBigramCount)) {
+        AKLOGE("Cannot flush the dictionary to file.");
+        mIsCorrupted = true;
+    }
+}
+
+void Ver4PatriciaTriePolicy::flushWithGC(const char *const filePath) {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: flushWithGC() is called for non-updatable dictionary.");
+        return;
+    }
+    if (!mWritingHelper.writeToDictFileWithGC(getRootPosition(), filePath)) {
+        AKLOGE("Cannot flush the dictionary to file with GC.");
+        mIsCorrupted = true;
+    }
+}
+
+bool Ver4PatriciaTriePolicy::needsToRunGC(const bool mindsBlockByGC) const {
+    if (!mBuffers->isUpdatable()) {
+        AKLOGI("Warning: needsToRunGC() is called for non-updatable dictionary.");
+        return false;
+    }
+    if (mBuffers->isNearSizeLimit()) {
+        // Additional buffer size is near the limit.
+        return true;
+    } else if (mHeaderPolicy->getExtendedRegionSize() + mDictBuffer->getUsedAdditionalBufferSize()
+            > Ver4DictConstants::MAX_DICT_EXTENDED_REGION_SIZE) {
+        // Total extended region size of the trie exceeds the limit.
+        return true;
+    } else if (mDictBuffer->getTailPosition() >= MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS
+            && mDictBuffer->getUsedAdditionalBufferSize() > 0) {
+        // Needs to reduce dictionary size.
+        return true;
+    } else if (mHeaderPolicy->isDecayingDict()) {
+        return ForgettingCurveUtils::needsToDecay(mindsBlockByGC, mUnigramCount, mBigramCount,
+                mHeaderPolicy);
+    }
+    return false;
+}
+
+void Ver4PatriciaTriePolicy::getProperty(const char *const query, const int queryLength,
+        char *const outResult, const int maxResultLength) {
+    const int compareLength = queryLength + 1 /* terminator */;
+    if (strncmp(query, UNIGRAM_COUNT_QUERY, compareLength) == 0) {
+        snprintf(outResult, maxResultLength, "%d", mUnigramCount);
+    } else if (strncmp(query, BIGRAM_COUNT_QUERY, compareLength) == 0) {
+        snprintf(outResult, maxResultLength, "%d", mBigramCount);
+    } else if (strncmp(query, MAX_UNIGRAM_COUNT_QUERY, compareLength) == 0) {
+        snprintf(outResult, maxResultLength, "%d",
+                mHeaderPolicy->isDecayingDict() ?
+                        ForgettingCurveUtils::getUnigramCountHardLimit(
+                                mHeaderPolicy->getMaxUnigramCount()) :
+                        static_cast<int>(Ver4DictConstants::MAX_DICTIONARY_SIZE));
+    } else if (strncmp(query, MAX_BIGRAM_COUNT_QUERY, compareLength) == 0) {
+        snprintf(outResult, maxResultLength, "%d",
+                mHeaderPolicy->isDecayingDict() ?
+                        ForgettingCurveUtils::getBigramCountHardLimit(
+                                mHeaderPolicy->getMaxBigramCount()) :
+                        static_cast<int>(Ver4DictConstants::MAX_DICTIONARY_SIZE));
+    }
+}
+
+const WordProperty Ver4PatriciaTriePolicy::getWordProperty(const int *const codePoints,
+        const int codePointCount) const {
+    const int ptNodePos = getTerminalPtNodePositionOfWord(codePoints, codePointCount,
+            false /* forceLowerCaseSearch */);
+    if (ptNodePos == NOT_A_DICT_POS) {
+        AKLOGE("getWordProperty is called for invalid word.");
+        return WordProperty();
+    }
+    const PtNodeParams ptNodeParams = mNodeReader.fetchNodeInfoInBufferFromPtNodePos(ptNodePos);
+    std::vector<int> codePointVector(ptNodeParams.getCodePoints(),
+            ptNodeParams.getCodePoints() + ptNodeParams.getCodePointCount());
+    const ProbabilityEntry probabilityEntry =
+            mBuffers->getProbabilityDictContent()->getProbabilityEntry(
+                    ptNodeParams.getTerminalId());
+    const HistoricalInfo *const historicalInfo = probabilityEntry.getHistoricalInfo();
+    // Fetch bigram information.
+    std::vector<BigramProperty> bigrams;
+    const int bigramListPos = getBigramsPositionOfPtNode(ptNodePos);
+    if (bigramListPos != NOT_A_DICT_POS) {
+        int bigramWord1CodePoints[MAX_WORD_LENGTH];
+        const BigramDictContent *const bigramDictContent = mBuffers->getBigramDictContent();
+        const TerminalPositionLookupTable *const terminalPositionLookupTable =
+                mBuffers->getTerminalPositionLookupTable();
+        bool hasNext = true;
+        int readingPos = bigramListPos;
+        while (hasNext) {
+            const BigramEntry bigramEntry =
+                    bigramDictContent->getBigramEntryAndAdvancePosition(&readingPos);
+            hasNext = bigramEntry.hasNext();
+            const int word1TerminalId = bigramEntry.getTargetTerminalId();
+            const int word1TerminalPtNodePos =
+                    terminalPositionLookupTable->getTerminalPtNodePosition(word1TerminalId);
+            if (word1TerminalPtNodePos == NOT_A_DICT_POS) {
+                continue;
+            }
+            // Word (unigram) probability
+            int word1Probability = NOT_A_PROBABILITY;
+            const int codePointCount = getCodePointsAndProbabilityAndReturnCodePointCount(
+                    word1TerminalPtNodePos, MAX_WORD_LENGTH, bigramWord1CodePoints,
+                    &word1Probability);
+            const std::vector<int> word1(bigramWord1CodePoints,
+                    bigramWord1CodePoints + codePointCount);
+            const HistoricalInfo *const historicalInfo = bigramEntry.getHistoricalInfo();
+            const int probability = bigramEntry.hasHistoricalInfo() ?
+                    ForgettingCurveUtils::decodeProbability(
+                            bigramEntry.getHistoricalInfo(), mHeaderPolicy) :
+                    getProbability(word1Probability, bigramEntry.getProbability());
+            bigrams.emplace_back(&word1, probability,
+                    historicalInfo->getTimeStamp(), historicalInfo->getLevel(),
+                    historicalInfo->getCount());
+        }
+    }
+    // Fetch shortcut information.
+    std::vector<UnigramProperty::ShortcutProperty> shortcuts;
+    int shortcutPos = getShortcutPositionOfPtNode(ptNodePos);
+    if (shortcutPos != NOT_A_DICT_POS) {
+        int shortcutTarget[MAX_WORD_LENGTH];
+        const ShortcutDictContent *const shortcutDictContent =
+                mBuffers->getShortcutDictContent();
+        bool hasNext = true;
+        while (hasNext) {
+            int shortcutTargetLength = 0;
+            int shortcutProbability = NOT_A_PROBABILITY;
+            shortcutDictContent->getShortcutEntryAndAdvancePosition(MAX_WORD_LENGTH, shortcutTarget,
+                    &shortcutTargetLength, &shortcutProbability, &hasNext, &shortcutPos);
+            const std::vector<int> target(shortcutTarget, shortcutTarget + shortcutTargetLength);
+            shortcuts.emplace_back(&target, shortcutProbability);
+        }
+    }
+    const UnigramProperty unigramProperty(ptNodeParams.isNotAWord(),
+            ptNodeParams.isBlacklisted(), ptNodeParams.getProbability(),
+            historicalInfo->getTimeStamp(), historicalInfo->getLevel(),
+            historicalInfo->getCount(), &shortcuts);
+    return WordProperty(&codePointVector, &unigramProperty, &bigrams);
+}
+
+int Ver4PatriciaTriePolicy::getNextWordAndNextToken(const int token, int *const outCodePoints) {
+    // TODO: Return code point count like other methods.
+    // Null termination.
+    outCodePoints[0] = 0;
+    if (token == 0) {
+        mTerminalPtNodePositionsForIteratingWords.clear();
+        DynamicPtReadingHelper::TraversePolicyToGetAllTerminalPtNodePositions traversePolicy(
+                &mTerminalPtNodePositionsForIteratingWords);
+        DynamicPtReadingHelper readingHelper(&mNodeReader, &mPtNodeArrayReader);
+        readingHelper.initWithPtNodeArrayPos(getRootPosition());
+        readingHelper.traverseAllPtNodesInPostorderDepthFirstManner(&traversePolicy);
+    }
+    const int terminalPtNodePositionsVectorSize =
+            static_cast<int>(mTerminalPtNodePositionsForIteratingWords.size());
+    if (token < 0 || token >= terminalPtNodePositionsVectorSize) {
+        AKLOGE("Given token %d is invalid.", token);
+        return 0;
+    }
+    const int terminalPtNodePos = mTerminalPtNodePositionsForIteratingWords[token];
+    int unigramProbability = NOT_A_PROBABILITY;
+    const int codePointCount = getCodePointsAndProbabilityAndReturnCodePointCount(
+            terminalPtNodePos, MAX_WORD_LENGTH, outCodePoints, &unigramProbability);
+    if (codePointCount < MAX_WORD_LENGTH) {
+        // Null termination. outCodePoints have to be null terminated or contain MAX_WORD_LENGTH
+        // code points.
+        outCodePoints[codePointCount] = 0;
+    }
+    const int nextToken = token + 1;
+    if (nextToken >= terminalPtNodePositionsVectorSize) {
+        // All words have been iterated.
+        mTerminalPtNodePositionsForIteratingWords.clear();
+        return 0;
+    }
+    return nextToken;
+}
+
+} // namespace v401
+} // namespace backward
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_policy.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_policy.h
new file mode 100644
index 0000000..2f8ad53
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_policy.h
@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT CHANGE THE LOGIC IN THIS FILE !!!!!
+ * Do not edit this file other than updating policy's interface.
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_POLICY_H
+#define LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_POLICY_H
+
+#include <vector>
+
+#include "defines.h"
+#include "suggest/core/policy/dictionary_structure_with_buffer_policy.h"
+#include "suggest/policyimpl/dictionary/header/header_policy.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_updating_helper.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/bigram/ver4_bigram_list_policy.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/shortcut/ver4_shortcut_list_policy.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_buffers.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_reader.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_writer.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_writing_helper.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_pt_node_array_reader.h"
+#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+} // namespace v401
+} // namespace backward
+class DicNode;
+namespace backward {
+namespace v401 {
+} // namespace v401
+} // namespace backward
+class DicNodeVector;
+namespace backward {
+namespace v401 {
+
+class Ver4PatriciaTriePolicy : public DictionaryStructureWithBufferPolicy {
+ public:
+    Ver4PatriciaTriePolicy(Ver4DictBuffers::Ver4DictBuffersPtr buffers)
+            : mBuffers(std::move(buffers)), mHeaderPolicy(mBuffers->getHeaderPolicy()),
+              mDictBuffer(mBuffers->getWritableTrieBuffer()),
+              mBigramPolicy(mBuffers->getMutableBigramDictContent(),
+                      mBuffers->getTerminalPositionLookupTable(), mHeaderPolicy),
+              mShortcutPolicy(mBuffers->getMutableShortcutDictContent(),
+                      mBuffers->getTerminalPositionLookupTable()),
+              mNodeReader(mDictBuffer, mBuffers->getProbabilityDictContent(), mHeaderPolicy),
+              mPtNodeArrayReader(mDictBuffer),
+              mNodeWriter(mDictBuffer, mBuffers.get(), mHeaderPolicy, &mNodeReader,
+                      &mPtNodeArrayReader, &mBigramPolicy, &mShortcutPolicy),
+              mUpdatingHelper(mDictBuffer, &mNodeReader, &mNodeWriter),
+              mWritingHelper(mBuffers.get()),
+              mUnigramCount(mHeaderPolicy->getUnigramCount()),
+              mBigramCount(mHeaderPolicy->getBigramCount()),
+              mTerminalPtNodePositionsForIteratingWords(), mIsCorrupted(false) {};
+
+    AK_FORCE_INLINE int getRootPosition() const {
+        return 0;
+    }
+
+    void createAndGetAllChildDicNodes(const DicNode *const dicNode,
+            DicNodeVector *const childDicNodes) const;
+
+    int getCodePointsAndProbabilityAndReturnCodePointCount(
+            const int terminalPtNodePos, const int maxCodePointCount, int *const outCodePoints,
+            int *const outUnigramProbability) const;
+
+    int getTerminalPtNodePositionOfWord(const int *const inWord,
+            const int length, const bool forceLowerCaseSearch) const;
+
+    int getProbability(const int unigramProbability, const int bigramProbability) const;
+
+    int getUnigramProbabilityOfPtNode(const int ptNodePos) const;
+
+    int getShortcutPositionOfPtNode(const int ptNodePos) const;
+
+    int getBigramsPositionOfPtNode(const int ptNodePos) const;
+
+    const DictionaryHeaderStructurePolicy *getHeaderStructurePolicy() const {
+        return mHeaderPolicy;
+    }
+
+    const DictionaryBigramsStructurePolicy *getBigramsStructurePolicy() const {
+        return &mBigramPolicy;
+    }
+
+    const DictionaryShortcutsStructurePolicy *getShortcutsStructurePolicy() const {
+        return &mShortcutPolicy;
+    }
+
+    bool addUnigramWord(const int *const word, const int length,
+            const UnigramProperty *const unigramProperty);
+
+    bool addBigramWords(const int *const word0, const int length0,
+            const BigramProperty *const bigramProperty);
+
+    bool removeBigramWords(const int *const word0, const int length0, const int *const word1,
+            const int length1);
+
+    void flush(const char *const filePath);
+
+    void flushWithGC(const char *const filePath);
+
+    bool needsToRunGC(const bool mindsBlockByGC) const;
+
+    void getProperty(const char *const query, const int queryLength, char *const outResult,
+            const int maxResultLength);
+
+    const WordProperty getWordProperty(const int *const codePoints,
+            const int codePointCount) const;
+
+    int getNextWordAndNextToken(const int token, int *const outCodePoints);
+
+    bool isCorrupted() const {
+        return mIsCorrupted;
+    }
+
+ private:
+    DISALLOW_IMPLICIT_CONSTRUCTORS(Ver4PatriciaTriePolicy);
+
+    static const char *const UNIGRAM_COUNT_QUERY;
+    static const char *const BIGRAM_COUNT_QUERY;
+    static const char *const MAX_UNIGRAM_COUNT_QUERY;
+    static const char *const MAX_BIGRAM_COUNT_QUERY;
+    // When the dictionary size is near the maximum size, we have to refuse dynamic operations to
+    // prevent the dictionary from overflowing.
+    static const int MARGIN_TO_REFUSE_DYNAMIC_OPERATIONS;
+    static const int MIN_DICT_SIZE_TO_REFUSE_DYNAMIC_OPERATIONS;
+
+    const Ver4DictBuffers::Ver4DictBuffersPtr mBuffers;
+    const HeaderPolicy *const mHeaderPolicy;
+    BufferWithExtendableBuffer *const mDictBuffer;
+    Ver4BigramListPolicy mBigramPolicy;
+    Ver4ShortcutListPolicy mShortcutPolicy;
+    Ver4PatriciaTrieNodeReader mNodeReader;
+    Ver4PtNodeArrayReader mPtNodeArrayReader;
+    Ver4PatriciaTrieNodeWriter mNodeWriter;
+    DynamicPtUpdatingHelper mUpdatingHelper;
+    Ver4PatriciaTrieWritingHelper mWritingHelper;
+    int mUnigramCount;
+    int mBigramCount;
+    std::vector<int> mTerminalPtNodePositionsForIteratingWords;
+    mutable bool mIsCorrupted;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif // LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_POLICY_H
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_reading_utils.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_reading_utils.cpp
new file mode 100644
index 0000000..6cc36fb
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_reading_utils.cpp
@@ -0,0 +1,39 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_reading_utils.cpp
+ */
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_reading_utils.h"
+
+#include "suggest/policyimpl/dictionary/utils/byte_array_utils.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+/* static */ int Ver4PatriciaTrieReadingUtils::getTerminalIdAndAdvancePosition(
+        const uint8_t *const buffer, int *pos) {
+    return ByteArrayUtils::readUint32AndAdvancePosition(buffer, pos);
+}
+
+} // namespace v401
+} // namespace backward
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_reading_utils.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_reading_utils.h
new file mode 100644
index 0000000..7417c26
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_reading_utils.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_reading_utils.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_READING_UTILS_H
+#define LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_READING_UTILS_H
+
+#include <cstdint>
+
+#include "defines.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+} // namespace v401
+} // namespace backward
+class BufferWithExtendableBuffer;
+namespace backward {
+namespace v401 {
+
+class Ver4PatriciaTrieReadingUtils {
+ public:
+    static int getTerminalIdAndAdvancePosition(const uint8_t *const buffer,
+            int *const pos);
+
+ private:
+    DISALLOW_IMPLICIT_CONSTRUCTORS(Ver4PatriciaTrieReadingUtils);
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_READING_UTILS_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_writing_helper.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_writing_helper.cpp
new file mode 100644
index 0000000..10f27be
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_writing_helper.cpp
@@ -0,0 +1,301 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.cpp
+ */
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_writing_helper.h"
+
+#include <cstring>
+#include <queue>
+
+#include "suggest/policyimpl/dictionary/header/header_policy.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/bigram/ver4_bigram_list_policy.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/shortcut/ver4_shortcut_list_policy.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_buffers.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_reader.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_node_writer.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_pt_node_array_reader.h"
+#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+#include "suggest/policyimpl/dictionary/utils/file_utils.h"
+#include "suggest/policyimpl/dictionary/utils/forgetting_curve_utils.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+bool Ver4PatriciaTrieWritingHelper::writeToDictFile(const char *const dictDirPath,
+        const int unigramCount, const int bigramCount) const {
+    const HeaderPolicy *const headerPolicy = mBuffers->getHeaderPolicy();
+    BufferWithExtendableBuffer headerBuffer(
+            BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE);
+    const int extendedRegionSize = headerPolicy->getExtendedRegionSize()
+            + mBuffers->getTrieBuffer()->getUsedAdditionalBufferSize();
+    if (!headerPolicy->fillInAndWriteHeaderToBuffer(false /* updatesLastDecayedTime */,
+            unigramCount, bigramCount, extendedRegionSize, &headerBuffer)) {
+        AKLOGE("Cannot write header structure to buffer. "
+                "updatesLastDecayedTime: %d, unigramCount: %d, bigramCount: %d, "
+                "extendedRegionSize: %d", false, unigramCount, bigramCount,
+                extendedRegionSize);
+        return false;
+    }
+    return mBuffers->flushHeaderAndDictBuffers(dictDirPath, &headerBuffer);
+}
+
+bool Ver4PatriciaTrieWritingHelper::writeToDictFileWithGC(const int rootPtNodeArrayPos,
+        const char *const dictDirPath) {
+    const HeaderPolicy *const headerPolicy = mBuffers->getHeaderPolicy();
+    Ver4DictBuffers::Ver4DictBuffersPtr dictBuffers(
+            Ver4DictBuffers::createVer4DictBuffers(headerPolicy,
+                    Ver4DictConstants::MAX_DICTIONARY_SIZE));
+    int unigramCount = 0;
+    int bigramCount = 0;
+    if (!runGC(rootPtNodeArrayPos, headerPolicy, dictBuffers.get(), &unigramCount, &bigramCount)) {
+        return false;
+    }
+    BufferWithExtendableBuffer headerBuffer(
+            BufferWithExtendableBuffer::DEFAULT_MAX_ADDITIONAL_BUFFER_SIZE);
+    if (!headerPolicy->fillInAndWriteHeaderToBuffer(true /* updatesLastDecayedTime */,
+            unigramCount, bigramCount, 0 /* extendedRegionSize */, &headerBuffer)) {
+        return false;
+    }
+    return dictBuffers->flushHeaderAndDictBuffers(dictDirPath, &headerBuffer);
+}
+
+bool Ver4PatriciaTrieWritingHelper::runGC(const int rootPtNodeArrayPos,
+        const HeaderPolicy *const headerPolicy, Ver4DictBuffers *const buffersToWrite,
+        int *const outUnigramCount, int *const outBigramCount) {
+    Ver4PatriciaTrieNodeReader ptNodeReader(mBuffers->getTrieBuffer(),
+            mBuffers->getProbabilityDictContent(), headerPolicy);
+    Ver4PtNodeArrayReader ptNodeArrayReader(mBuffers->getTrieBuffer());
+    Ver4BigramListPolicy bigramPolicy(mBuffers->getMutableBigramDictContent(),
+            mBuffers->getTerminalPositionLookupTable(), headerPolicy);
+    Ver4ShortcutListPolicy shortcutPolicy(mBuffers->getMutableShortcutDictContent(),
+            mBuffers->getTerminalPositionLookupTable());
+    Ver4PatriciaTrieNodeWriter ptNodeWriter(mBuffers->getWritableTrieBuffer(),
+            mBuffers, headerPolicy, &ptNodeReader, &ptNodeArrayReader, &bigramPolicy,
+            &shortcutPolicy);
+
+    DynamicPtReadingHelper readingHelper(&ptNodeReader, &ptNodeArrayReader);
+    readingHelper.initWithPtNodeArrayPos(rootPtNodeArrayPos);
+    DynamicPtGcEventListeners
+            ::TraversePolicyToUpdateUnigramProbabilityAndMarkUselessPtNodesAsDeleted
+                    traversePolicyToUpdateUnigramProbabilityAndMarkUselessPtNodesAsDeleted(
+                            &ptNodeWriter);
+    if (!readingHelper.traverseAllPtNodesInPostorderDepthFirstManner(
+            &traversePolicyToUpdateUnigramProbabilityAndMarkUselessPtNodesAsDeleted)) {
+        return false;
+    }
+    const int unigramCount = traversePolicyToUpdateUnigramProbabilityAndMarkUselessPtNodesAsDeleted
+            .getValidUnigramCount();
+    const int maxUnigramCount = headerPolicy->getMaxUnigramCount();
+    if (headerPolicy->isDecayingDict() && unigramCount > maxUnigramCount) {
+        if (!truncateUnigrams(&ptNodeReader, &ptNodeWriter, maxUnigramCount)) {
+            AKLOGE("Cannot remove unigrams. current: %d, max: %d", unigramCount,
+                    maxUnigramCount);
+            return false;
+        }
+    }
+
+    readingHelper.initWithPtNodeArrayPos(rootPtNodeArrayPos);
+    DynamicPtGcEventListeners::TraversePolicyToUpdateBigramProbability
+            traversePolicyToUpdateBigramProbability(&ptNodeWriter);
+    if (!readingHelper.traverseAllPtNodesInPostorderDepthFirstManner(
+            &traversePolicyToUpdateBigramProbability)) {
+        return false;
+    }
+    const int bigramCount = traversePolicyToUpdateBigramProbability.getValidBigramEntryCount();
+    const int maxBigramCount = headerPolicy->getMaxBigramCount();
+    if (headerPolicy->isDecayingDict() && bigramCount > maxBigramCount) {
+        if (!truncateBigrams(maxBigramCount)) {
+            AKLOGE("Cannot remove bigrams. current: %d, max: %d", bigramCount, maxBigramCount);
+            return false;
+        }
+    }
+
+    // Mapping from positions in mBuffer to positions in bufferToWrite.
+    PtNodeWriter::DictPositionRelocationMap dictPositionRelocationMap;
+    readingHelper.initWithPtNodeArrayPos(rootPtNodeArrayPos);
+    Ver4PatriciaTrieNodeWriter ptNodeWriterForNewBuffers(buffersToWrite->getWritableTrieBuffer(),
+            buffersToWrite, headerPolicy, &ptNodeReader, &ptNodeArrayReader, &bigramPolicy,
+            &shortcutPolicy);
+    DynamicPtGcEventListeners::TraversePolicyToPlaceAndWriteValidPtNodesToBuffer
+            traversePolicyToPlaceAndWriteValidPtNodesToBuffer(&ptNodeWriterForNewBuffers,
+                    buffersToWrite->getWritableTrieBuffer(), &dictPositionRelocationMap);
+    if (!readingHelper.traverseAllPtNodesInPtNodeArrayLevelPreorderDepthFirstManner(
+            &traversePolicyToPlaceAndWriteValidPtNodesToBuffer)) {
+        return false;
+    }
+
+    // Create policy instances for the GCed dictionary.
+    Ver4PatriciaTrieNodeReader newPtNodeReader(buffersToWrite->getTrieBuffer(),
+            buffersToWrite->getProbabilityDictContent(), headerPolicy);
+    Ver4PtNodeArrayReader newPtNodeArrayreader(buffersToWrite->getTrieBuffer());
+    Ver4BigramListPolicy newBigramPolicy(buffersToWrite->getMutableBigramDictContent(),
+            buffersToWrite->getTerminalPositionLookupTable(), headerPolicy);
+    Ver4ShortcutListPolicy newShortcutPolicy(buffersToWrite->getMutableShortcutDictContent(),
+            buffersToWrite->getTerminalPositionLookupTable());
+    Ver4PatriciaTrieNodeWriter newPtNodeWriter(buffersToWrite->getWritableTrieBuffer(),
+            buffersToWrite, headerPolicy, &newPtNodeReader, &newPtNodeArrayreader, &newBigramPolicy,
+            &newShortcutPolicy);
+    // Re-assign terminal IDs for valid terminal PtNodes.
+    TerminalPositionLookupTable::TerminalIdMap terminalIdMap;
+    if(!buffersToWrite->getMutableTerminalPositionLookupTable()->runGCTerminalIds(
+            &terminalIdMap)) {
+        return false;
+    }
+    // Run GC for probability dict content.
+    if (!buffersToWrite->getMutableProbabilityDictContent()->runGC(&terminalIdMap,
+            mBuffers->getProbabilityDictContent())) {
+        return false;
+    }
+    // Run GC for bigram dict content.
+    if(!buffersToWrite->getMutableBigramDictContent()->runGC(&terminalIdMap,
+            mBuffers->getBigramDictContent(), outBigramCount)) {
+        return false;
+    }
+    // Run GC for shortcut dict content.
+    if(!buffersToWrite->getMutableShortcutDictContent()->runGC(&terminalIdMap,
+            mBuffers->getShortcutDictContent())) {
+        return false;
+    }
+    DynamicPtReadingHelper newDictReadingHelper(&newPtNodeReader, &newPtNodeArrayreader);
+    newDictReadingHelper.initWithPtNodeArrayPos(rootPtNodeArrayPos);
+    DynamicPtGcEventListeners::TraversePolicyToUpdateAllPositionFields
+            traversePolicyToUpdateAllPositionFields(&newPtNodeWriter, &dictPositionRelocationMap);
+    if (!newDictReadingHelper.traverseAllPtNodesInPtNodeArrayLevelPreorderDepthFirstManner(
+            &traversePolicyToUpdateAllPositionFields)) {
+        return false;
+    }
+    newDictReadingHelper.initWithPtNodeArrayPos(rootPtNodeArrayPos);
+    TraversePolicyToUpdateAllPtNodeFlagsAndTerminalIds
+            traversePolicyToUpdateAllPtNodeFlagsAndTerminalIds(&newPtNodeWriter, &terminalIdMap);
+    if (!newDictReadingHelper.traverseAllPtNodesInPostorderDepthFirstManner(
+            &traversePolicyToUpdateAllPtNodeFlagsAndTerminalIds)) {
+        return false;
+    }
+    *outUnigramCount = traversePolicyToUpdateAllPositionFields.getUnigramCount();
+    return true;
+}
+
+bool Ver4PatriciaTrieWritingHelper::truncateUnigrams(
+        const Ver4PatriciaTrieNodeReader *const ptNodeReader,
+        Ver4PatriciaTrieNodeWriter *const ptNodeWriter, const int maxUnigramCount) {
+    const TerminalPositionLookupTable *const terminalPosLookupTable =
+            mBuffers->getTerminalPositionLookupTable();
+    const int nextTerminalId = terminalPosLookupTable->getNextTerminalId();
+    std::priority_queue<DictProbability, std::vector<DictProbability>, DictProbabilityComparator>
+            priorityQueue;
+    for (int i = 0; i < nextTerminalId; ++i) {
+        const int terminalPos = terminalPosLookupTable->getTerminalPtNodePosition(i);
+        if (terminalPos == NOT_A_DICT_POS) {
+            continue;
+        }
+        const ProbabilityEntry probabilityEntry =
+                mBuffers->getProbabilityDictContent()->getProbabilityEntry(i);
+        const int probability = probabilityEntry.hasHistoricalInfo() ?
+                ForgettingCurveUtils::decodeProbability(
+                        probabilityEntry.getHistoricalInfo(), mBuffers->getHeaderPolicy()) :
+                probabilityEntry.getProbability();
+        priorityQueue.push(DictProbability(terminalPos, probability,
+                probabilityEntry.getHistoricalInfo()->getTimeStamp()));
+    }
+
+    // Delete unigrams.
+    while (static_cast<int>(priorityQueue.size()) > maxUnigramCount) {
+        const int ptNodePos = priorityQueue.top().getDictPos();
+        const PtNodeParams ptNodeParams =
+                ptNodeReader->fetchNodeInfoInBufferFromPtNodePos(ptNodePos);
+        if (!ptNodeWriter->markPtNodeAsWillBecomeNonTerminal(&ptNodeParams)) {
+            AKLOGE("Cannot mark PtNode as willBecomeNonterminal. PtNode pos: %d", ptNodePos);
+            return false;
+        }
+        priorityQueue.pop();
+    }
+    return true;
+}
+
+bool Ver4PatriciaTrieWritingHelper::truncateBigrams(const int maxBigramCount) {
+    const TerminalPositionLookupTable *const terminalPosLookupTable =
+            mBuffers->getTerminalPositionLookupTable();
+    const int nextTerminalId = terminalPosLookupTable->getNextTerminalId();
+    std::priority_queue<DictProbability, std::vector<DictProbability>, DictProbabilityComparator>
+            priorityQueue;
+    BigramDictContent *const bigramDictContent = mBuffers->getMutableBigramDictContent();
+    for (int i = 0; i < nextTerminalId; ++i) {
+        const int bigramListPos = bigramDictContent->getBigramListHeadPos(i);
+        if (bigramListPos == NOT_A_DICT_POS) {
+            continue;
+        }
+        bool hasNext = true;
+        int readingPos = bigramListPos;
+        while (hasNext) {
+            const int entryPos = readingPos;
+            const BigramEntry bigramEntry =
+                    bigramDictContent->getBigramEntryAndAdvancePosition(&readingPos);
+            hasNext = bigramEntry.hasNext();
+            if (!bigramEntry.isValid()) {
+                continue;
+            }
+            const int probability = bigramEntry.hasHistoricalInfo() ?
+                    ForgettingCurveUtils::decodeProbability(
+                            bigramEntry.getHistoricalInfo(), mBuffers->getHeaderPolicy()) :
+                    bigramEntry.getProbability();
+            priorityQueue.push(DictProbability(entryPos, probability,
+                    bigramEntry.getHistoricalInfo()->getTimeStamp()));
+        }
+    }
+
+    // Delete bigrams.
+    while (static_cast<int>(priorityQueue.size()) > maxBigramCount) {
+        const int entryPos = priorityQueue.top().getDictPos();
+        const BigramEntry bigramEntry = bigramDictContent->getBigramEntry(entryPos);
+        const BigramEntry invalidatedBigramEntry = bigramEntry.getInvalidatedEntry();
+        if (!bigramDictContent->writeBigramEntry(&invalidatedBigramEntry, entryPos)) {
+            AKLOGE("Cannot write bigram entry to remove. pos: %d", entryPos);
+            return false;
+        }
+        priorityQueue.pop();
+    }
+    return true;
+}
+
+bool Ver4PatriciaTrieWritingHelper::TraversePolicyToUpdateAllPtNodeFlagsAndTerminalIds
+        ::onVisitingPtNode(const PtNodeParams *const ptNodeParams) {
+    if (!ptNodeParams->isTerminal()) {
+        return true;
+    }
+    TerminalPositionLookupTable::TerminalIdMap::const_iterator it =
+            mTerminalIdMap->find(ptNodeParams->getTerminalId());
+    if (it == mTerminalIdMap->end()) {
+        AKLOGE("terminal Id %d is not in the terminal position map. map size: %zd",
+                ptNodeParams->getTerminalId(), mTerminalIdMap->size());
+        return false;
+    }
+    if (!mPtNodeWriter->updateTerminalId(ptNodeParams, it->second)) {
+        AKLOGE("Cannot update terminal id. %d -> %d", it->first, it->second);
+    }
+    return mPtNodeWriter->updatePtNodeHasBigramsAndShortcutTargetsFlags(ptNodeParams);
+}
+
+} // namespace v401
+} // namespace backward
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_writing_helper.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_writing_helper.h
new file mode 100644
index 0000000..be44aaa
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_writing_helper.h
@@ -0,0 +1,140 @@
+/*
+ * Copyright (C) 2013, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_WRITING_HELPER_H
+#define LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_WRITING_HELPER_H
+
+#include "defines.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/content/terminal_position_lookup_table.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+} // namespace v401
+} // namespace backward
+class HeaderPolicy;
+namespace backward {
+namespace v401 {
+class Ver4DictBuffers;
+class Ver4PatriciaTrieNodeReader;
+class Ver4PatriciaTrieNodeWriter;
+
+class Ver4PatriciaTrieWritingHelper {
+ public:
+    Ver4PatriciaTrieWritingHelper(Ver4DictBuffers *const buffers)
+            : mBuffers(buffers) {}
+
+    bool writeToDictFile(const char *const dictDirPath, const int unigramCount,
+            const int bigramCount) const;
+
+    // This method cannot be const because the original dictionary buffer will be updated to detect
+    // useless PtNodes during GC.
+    bool writeToDictFileWithGC(const int rootPtNodeArrayPos, const char *const dictDirPath);
+
+ private:
+    DISALLOW_IMPLICIT_CONSTRUCTORS(Ver4PatriciaTrieWritingHelper);
+
+    class TraversePolicyToUpdateAllPtNodeFlagsAndTerminalIds
+            : public DynamicPtReadingHelper::TraversingEventListener {
+     public:
+        TraversePolicyToUpdateAllPtNodeFlagsAndTerminalIds(
+                Ver4PatriciaTrieNodeWriter *const ptNodeWriter,
+                const TerminalPositionLookupTable::TerminalIdMap *const terminalIdMap)
+                : mPtNodeWriter(ptNodeWriter), mTerminalIdMap(terminalIdMap) {}
+
+        bool onAscend() { return true; }
+
+        bool onDescend(const int ptNodeArrayPos) { return true; }
+
+        bool onReadingPtNodeArrayTail() { return true; }
+
+        bool onVisitingPtNode(const PtNodeParams *const ptNodeParams);
+
+     private:
+        DISALLOW_IMPLICIT_CONSTRUCTORS(TraversePolicyToUpdateAllPtNodeFlagsAndTerminalIds);
+
+        Ver4PatriciaTrieNodeWriter *const mPtNodeWriter;
+        const TerminalPositionLookupTable::TerminalIdMap *const mTerminalIdMap;
+    };
+
+    // For truncateUnigrams() and truncateBigrams().
+    class DictProbability {
+     public:
+        DictProbability(const int dictPos, const int probability, const int timestamp)
+                : mDictPos(dictPos), mProbability(probability), mTimestamp(timestamp) {}
+
+        int getDictPos() const {
+            return mDictPos;
+        }
+
+        int getProbability() const {
+            return mProbability;
+        }
+
+        int getTimestamp() const {
+            return mTimestamp;
+        }
+
+     private:
+        DISALLOW_DEFAULT_CONSTRUCTOR(DictProbability);
+
+        int mDictPos;
+        int mProbability;
+        int mTimestamp;
+    };
+
+    // For truncateUnigrams() and truncateBigrams().
+    class DictProbabilityComparator {
+     public:
+        bool operator()(const DictProbability &left, const DictProbability &right) {
+            if (left.getProbability() != right.getProbability()) {
+                return left.getProbability() > right.getProbability();
+            }
+            if (left.getTimestamp() != right.getTimestamp()) {
+                return left.getTimestamp() < right.getTimestamp();
+            }
+            return left.getDictPos() > right.getDictPos();
+        }
+
+     private:
+        DISALLOW_ASSIGNMENT_OPERATOR(DictProbabilityComparator);
+    };
+
+    bool runGC(const int rootPtNodeArrayPos, const HeaderPolicy *const headerPolicy,
+            Ver4DictBuffers *const buffersToWrite, int *const outUnigramCount,
+            int *const outBigramCount);
+
+    bool truncateUnigrams(const Ver4PatriciaTrieNodeReader *const ptNodeReader,
+            Ver4PatriciaTrieNodeWriter *const ptNodeWriter, const int maxUnigramCount);
+
+    bool truncateBigrams(const int maxBigramCount);
+
+    Ver4DictBuffers *const mBuffers;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+
+#endif /* LATINIME_BACKWARD_V401_VER4_PATRICIA_TRIE_WRITING_HELPER_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_pt_node_array_reader.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_pt_node_array_reader.cpp
new file mode 100644
index 0000000..33e4e55
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_pt_node_array_reader.cpp
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_pt_node_array_reader.cpp
+ */
+
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_pt_node_array_reader.h"
+
+#include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
+#include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+bool Ver4PtNodeArrayReader::readPtNodeArrayInfoAndReturnIfValid(const int ptNodeArrayPos,
+        int *const outPtNodeCount, int *const outFirstPtNodePos) const {
+    if (ptNodeArrayPos < 0 || ptNodeArrayPos >= mBuffer->getTailPosition()) {
+        // Reading invalid position because of a bug or a broken dictionary.
+        AKLOGE("Reading PtNode array info from invalid dictionary position: %d, dict size: %d",
+                ptNodeArrayPos, mBuffer->getTailPosition());
+        ASSERT(false);
+        return false;
+    }
+    const bool usesAdditionalBuffer = mBuffer->isInAdditionalBuffer(ptNodeArrayPos);
+    const uint8_t *const dictBuf = mBuffer->getBuffer(usesAdditionalBuffer);
+    int readingPos = ptNodeArrayPos;
+    if (usesAdditionalBuffer) {
+        readingPos -= mBuffer->getOriginalBufferSize();
+    }
+    const int ptNodeCountInArray = PatriciaTrieReadingUtils::getPtNodeArraySizeAndAdvancePosition(
+            dictBuf, &readingPos);
+    if (usesAdditionalBuffer) {
+        readingPos += mBuffer->getOriginalBufferSize();
+    }
+    if (ptNodeCountInArray < 0) {
+        AKLOGE("Invalid PtNode count in an array: %d.", ptNodeCountInArray);
+        return false;
+    }
+    *outPtNodeCount = ptNodeCountInArray;
+    *outFirstPtNodePos = readingPos;
+    return true;
+}
+
+bool Ver4PtNodeArrayReader::readForwardLinkAndReturnIfValid(const int forwordLinkPos,
+        int *const outNextPtNodeArrayPos) const {
+    if (forwordLinkPos < 0 || forwordLinkPos >= mBuffer->getTailPosition()) {
+        // Reading invalid position because of bug or broken dictionary.
+        AKLOGE("Reading forward link from invalid dictionary position: %d, dict size: %d",
+                forwordLinkPos, mBuffer->getTailPosition());
+        ASSERT(false);
+        return false;
+    }
+    const bool usesAdditionalBuffer = mBuffer->isInAdditionalBuffer(forwordLinkPos);
+    const uint8_t *const dictBuf = mBuffer->getBuffer(usesAdditionalBuffer);
+    int readingPos = forwordLinkPos;
+    if (usesAdditionalBuffer) {
+        readingPos -= mBuffer->getOriginalBufferSize();
+    }
+    const int nextPtNodeArrayOffset =
+            DynamicPtReadingUtils::getForwardLinkPosition(dictBuf, readingPos);
+    if (DynamicPtReadingUtils::isValidForwardLinkPosition(nextPtNodeArrayOffset)) {
+        *outNextPtNodeArrayPos = forwordLinkPos + nextPtNodeArrayOffset;
+    } else {
+        *outNextPtNodeArrayPos = NOT_A_DICT_POS;
+    }
+    return true;
+}
+
+} // namespace v401
+} // namespace backward
+} // namespace latinime
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_pt_node_array_reader.h b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_pt_node_array_reader.h
new file mode 100644
index 0000000..3a7eefa
--- /dev/null
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/backward/v401/ver4_pt_node_array_reader.h
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2014, The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * !!!!! DO NOT EDIT THIS FILE !!!!!
+ *
+ * This file was generated from
+ *   suggest/policyimpl/dictionary/structure/v4/ver4_pt_node_array_reader.h
+ */
+
+#ifndef LATINIME_BACKWARD_V401_VER4_PT_NODE_ARRAY_READER_H
+#define LATINIME_BACKWARD_V401_VER4_PT_NODE_ARRAY_READER_H
+
+#include "defines.h"
+#include "suggest/policyimpl/dictionary/structure/pt_common/pt_node_array_reader.h"
+
+namespace latinime {
+namespace backward {
+namespace v401 {
+
+} // namespace v401
+} // namespace backward
+class BufferWithExtendableBuffer;
+namespace backward {
+namespace v401 {
+
+class Ver4PtNodeArrayReader : public PtNodeArrayReader {
+ public:
+    Ver4PtNodeArrayReader(const BufferWithExtendableBuffer *const buffer) : mBuffer(buffer) {};
+
+    virtual bool readPtNodeArrayInfoAndReturnIfValid(const int ptNodeArrayPos,
+            int *const outPtNodeCount, int *const outFirstPtNodePos) const;
+    virtual bool readForwardLinkAndReturnIfValid(const int forwordLinkPos,
+            int *const outNextPtNodeArrayPos) const;
+
+ private:
+    DISALLOW_COPY_AND_ASSIGN(Ver4PtNodeArrayReader);
+
+    const BufferWithExtendableBuffer *const mBuffer;
+};
+} // namespace v401
+} // namespace backward
+} // namespace latinime
+#endif /* LATINIME_BACKWARD_V401_VER4_PT_NODE_ARRAY_READER_H */
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp
index c4d1860..59f1f29 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.cpp
@@ -19,6 +19,9 @@
 #include <climits>
 
 #include "defines.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_buffers.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_constants.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_patricia_trie_policy.h"
 #include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
 #include "suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.h"
 #include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h"
@@ -42,7 +45,7 @@
         if (isUpdatable) {
             AKLOGE("One file dictionaries don't support updating. path: %s", path);
             ASSERT(false);
-            return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(nullptr);
+            return nullptr;
         }
         return newPolicyForFileDict(path, bufOffset, size);
     }
@@ -54,26 +57,43 @@
                 const DictionaryHeaderStructurePolicy::AttributeMap *const attributeMap) {
     FormatUtils::FORMAT_VERSION dictFormatVersion = FormatUtils::getFormatVersion(formatVersion);
     switch (dictFormatVersion) {
-        case FormatUtils::VERSION_4_ONLY_FOR_TESTING:
         case FormatUtils::VERSION_4: {
-            HeaderPolicy headerPolicy(dictFormatVersion, locale, attributeMap);
-            Ver4DictBuffers::Ver4DictBuffersPtr dictBuffers =
-                    Ver4DictBuffers::createVer4DictBuffers(&headerPolicy,
-                            Ver4DictConstants::MAX_DICT_EXTENDED_REGION_SIZE);
-            if (!DynamicPtWritingUtils::writeEmptyDictionary(
-                    dictBuffers->getWritableTrieBuffer(), 0 /* rootPos */)) {
-                AKLOGE("Empty ver4 dictionary structure cannot be created on memory.");
-                return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(nullptr);
-            }
-            return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(
-                    new Ver4PatriciaTriePolicy(std::move(dictBuffers)));
+            return newPolicyForOnMemoryV4Dict<backward::v401::Ver4DictConstants,
+                    backward::v401::Ver4DictBuffers,
+                    backward::v401::Ver4DictBuffers::Ver4DictBuffersPtr,
+                    backward::v401::Ver4PatriciaTriePolicy>(
+                            dictFormatVersion, locale, attributeMap);
+        }
+        case FormatUtils::VERSION_4_ONLY_FOR_TESTING:
+        case FormatUtils::VERSION_4_DEV: {
+            return newPolicyForOnMemoryV4Dict<Ver4DictConstants, Ver4DictBuffers,
+                    Ver4DictBuffers::Ver4DictBuffersPtr, Ver4PatriciaTriePolicy>(
+                            dictFormatVersion, locale, attributeMap);
         }
         default:
             AKLOGE("DICT: dictionary format %d is not supported for on memory dictionary",
                     formatVersion);
             break;
     }
-    return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(nullptr);
+    return nullptr;
+}
+
+template<class DictConstants, class DictBuffers, class DictBuffersPtr, class StructurePolicy>
+/* static */ DictionaryStructureWithBufferPolicy::StructurePolicyPtr
+        DictionaryStructureWithBufferPolicyFactory::newPolicyForOnMemoryV4Dict(
+                const FormatUtils::FORMAT_VERSION formatVersion,
+                const std::vector<int> &locale,
+                const DictionaryHeaderStructurePolicy::AttributeMap *const attributeMap) {
+    HeaderPolicy headerPolicy(formatVersion, locale, attributeMap);
+    DictBuffersPtr dictBuffers = DictBuffers::createVer4DictBuffers(&headerPolicy,
+            DictConstants::MAX_DICT_EXTENDED_REGION_SIZE);
+    if (!DynamicPtWritingUtils::writeEmptyDictionary(
+            dictBuffers->getWritableTrieBuffer(), 0 /* rootPos */)) {
+        AKLOGE("Empty ver4 dictionary structure cannot be created on memory.");
+        return nullptr;
+    }
+    return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(
+            new StructurePolicy(std::move(dictBuffers)));
 }
 
 /* static */ DictionaryStructureWithBufferPolicy::StructurePolicyPtr
@@ -84,10 +104,10 @@
     getHeaderFilePathInDictDir(path, headerFilePathBufSize, headerFilePath);
     // Allocated buffer in MmapedBuffer::openBuffer() will be freed in the destructor of
     // MmappedBufferPtr if the instance has the responsibility.
-    MmappedBuffer::MmappedBufferPtr mmappedBuffer(
-            MmappedBuffer::openBuffer(headerFilePath, isUpdatable));
+    MmappedBuffer::MmappedBufferPtr mmappedBuffer =
+            MmappedBuffer::openBuffer(headerFilePath, isUpdatable);
     if (!mmappedBuffer) {
-        return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(nullptr);
+        return nullptr;
     }
     const FormatUtils::FORMAT_VERSION formatVersion = FormatUtils::detectFormatVersion(
             mmappedBuffer->getBuffer(), mmappedBuffer->getBufferSize());
@@ -95,34 +115,50 @@
         case FormatUtils::VERSION_2:
             AKLOGE("Given path is a directory but the format is version 2. path: %s", path);
             break;
-        case FormatUtils::VERSION_4_ONLY_FOR_TESTING:
         case FormatUtils::VERSION_4: {
-            const int dictDirPathBufSize = strlen(headerFilePath) + 1 /* terminator */;
-            char dictPath[dictDirPathBufSize];
-            if (!FileUtils::getFilePathWithoutSuffix(headerFilePath,
-                    Ver4DictConstants::HEADER_FILE_EXTENSION, dictDirPathBufSize, dictPath)) {
-                AKLOGE("Dictionary file name is not valid as a ver4 dictionary. path: %s", path);
-                ASSERT(false);
-                return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(nullptr);
-            }
-            Ver4DictBuffers::Ver4DictBuffersPtr dictBuffers(
-                    Ver4DictBuffers::openVer4DictBuffers(dictPath, std::move(mmappedBuffer),
-                            formatVersion));
-            if (!dictBuffers || !dictBuffers->isValid()) {
-                AKLOGE("DICT: The dictionary doesn't satisfy ver4 format requirements. path: %s",
-                        path);
-                ASSERT(false);
-                return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(nullptr);
-            }
-            return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(
-                    new Ver4PatriciaTriePolicy(std::move(dictBuffers)));
+            return newPolicyForV4Dict<backward::v401::Ver4DictConstants,
+                    backward::v401::Ver4DictBuffers,
+                    backward::v401::Ver4DictBuffers::Ver4DictBuffersPtr,
+                    backward::v401::Ver4PatriciaTriePolicy>(
+                            headerFilePath, formatVersion, std::move(mmappedBuffer));
+        }
+        case FormatUtils::VERSION_4_ONLY_FOR_TESTING:
+        case FormatUtils::VERSION_4_DEV: {
+            return newPolicyForV4Dict<Ver4DictConstants, Ver4DictBuffers,
+                    Ver4DictBuffers::Ver4DictBuffersPtr, Ver4PatriciaTriePolicy>(
+                            headerFilePath, formatVersion, std::move(mmappedBuffer));
         }
         default:
             AKLOGE("DICT: dictionary format is unknown, bad magic number. path: %s", path);
             break;
     }
     ASSERT(false);
-    return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(nullptr);
+    return nullptr;
+}
+
+template<class DictConstants, class DictBuffers, class DictBuffersPtr, class StructurePolicy>
+/* static */ DictionaryStructureWithBufferPolicy::StructurePolicyPtr
+        DictionaryStructureWithBufferPolicyFactory::newPolicyForV4Dict(
+                const char *const headerFilePath, const FormatUtils::FORMAT_VERSION formatVersion,
+                MmappedBuffer::MmappedBufferPtr &&mmappedBuffer) {
+    const int dictDirPathBufSize = strlen(headerFilePath) + 1 /* terminator */;
+    char dictPath[dictDirPathBufSize];
+    if (!FileUtils::getFilePathWithoutSuffix(headerFilePath,
+            DictConstants::HEADER_FILE_EXTENSION, dictDirPathBufSize, dictPath)) {
+        AKLOGE("Dictionary file name is not valid as a ver4 dictionary. path: %s", path);
+        ASSERT(false);
+        return nullptr;
+    }
+    DictBuffersPtr dictBuffers =
+            DictBuffers::openVer4DictBuffers(dictPath, std::move(mmappedBuffer), formatVersion);
+    if (!dictBuffers || !dictBuffers->isValid()) {
+        AKLOGE("DICT: The dictionary doesn't satisfy ver4 format requirements. path: %s",
+                path);
+        ASSERT(false);
+        return nullptr;
+    }
+    return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(
+            new StructurePolicy(std::move(dictBuffers)));
 }
 
 /* static */ DictionaryStructureWithBufferPolicy::StructurePolicyPtr
@@ -133,7 +169,7 @@
     MmappedBuffer::MmappedBufferPtr mmappedBuffer(
             MmappedBuffer::openBuffer(path, bufOffset, size, false /* isUpdatable */));
     if (!mmappedBuffer) {
-        return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(nullptr);
+        return nullptr;
     }
     switch (FormatUtils::detectFormatVersion(mmappedBuffer->getBuffer(),
             mmappedBuffer->getBufferSize())) {
@@ -142,6 +178,7 @@
                     new PatriciaTriePolicy(std::move(mmappedBuffer)));
         case FormatUtils::VERSION_4_ONLY_FOR_TESTING:
         case FormatUtils::VERSION_4:
+        case FormatUtils::VERSION_4_DEV:
             AKLOGE("Given path is a file but the format is version 4. path: %s", path);
             break;
         default:
@@ -149,7 +186,7 @@
             break;
     }
     ASSERT(false);
-    return DictionaryStructureWithBufferPolicy::StructurePolicyPtr(nullptr);
+    return nullptr;
 }
 
 /* static */ void DictionaryStructureWithBufferPolicyFactory::getHeaderFilePathInDictDir(
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.h b/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.h
index f71447e..768454d 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/dictionary_structure_with_buffer_policy_factory.h
@@ -22,6 +22,8 @@
 #include "defines.h"
 #include "suggest/core/policy/dictionary_header_structure_policy.h"
 #include "suggest/core/policy/dictionary_structure_with_buffer_policy.h"
+#include "suggest/policyimpl/dictionary/utils/format_utils.h"
+#include "suggest/policyimpl/dictionary/utils/mmapped_buffer.h"
 
 namespace latinime {
 
@@ -32,16 +34,26 @@
                     const int size, const bool isUpdatable);
 
     static DictionaryStructureWithBufferPolicy::StructurePolicyPtr
-            newPolicyForOnMemoryDict(const int formatVersion,
-                    const std::vector<int> &locale,
+            newPolicyForOnMemoryDict(const int formatVersion, const std::vector<int> &locale,
                     const DictionaryHeaderStructurePolicy::AttributeMap *const attributeMap);
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(DictionaryStructureWithBufferPolicyFactory);
 
+    template<class DictConstants, class DictBuffers, class DictBuffersPtr, class StructurePolicy>
+    static DictionaryStructureWithBufferPolicy::StructurePolicyPtr
+            newPolicyForOnMemoryV4Dict(const FormatUtils::FORMAT_VERSION formatVersion,
+                    const std::vector<int> &locale,
+                    const DictionaryHeaderStructurePolicy::AttributeMap *const attributeMap);
+
     static DictionaryStructureWithBufferPolicy::StructurePolicyPtr
             newPolicyForDirectoryDict(const char *const path, const bool isUpdatable);
 
+    template<class DictConstants, class DictBuffers, class DictBuffersPtr, class StructurePolicy>
+    static DictionaryStructureWithBufferPolicy::StructurePolicyPtr newPolicyForV4Dict(
+            const char *const headerFilePath, const FormatUtils::FORMAT_VERSION formatVersion,
+                    MmappedBuffer::MmappedBufferPtr &&mmappedBuffer);
+
     static DictionaryStructureWithBufferPolicy::StructurePolicyPtr
             newPolicyForFileDict(const char *const path, const int bufOffset, const int size);
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.cpp
index 8f42df6..028e9ec 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_gc_event_listeners.cpp
@@ -29,10 +29,10 @@
     // PtNode is useless when the PtNode is not a terminal and doesn't have any not useless
     // children.
     bool isUselessPtNode = !ptNodeParams->isTerminal();
-    if (ptNodeParams->isTerminal()) {
+    if (ptNodeParams->isTerminal() && !ptNodeParams->representsNonWordInfo()) {
         bool needsToKeepPtNode = true;
-        if (!mPtNodeWriter->updatePtNodeProbabilityAndGetNeedsToKeepPtNodeAfterGC(ptNodeParams,
-                &needsToKeepPtNode)) {
+        if (!mPtNodeWriter->updatePtNodeProbabilityAndGetNeedsToKeepPtNodeAfterGC(
+                ptNodeParams, &needsToKeepPtNode)) {
             AKLOGE("Cannot update PtNode probability or get needs to keep PtNode after GC.");
             return false;
         }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h b/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h
index 91192fc..5704c2e 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/pt_common/pt_node_params.h
@@ -23,6 +23,7 @@
 #include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_utils.h"
 #include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
 #include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_constants.h"
+#include "utils/char_utils.h"
 
 namespace latinime {
 
@@ -158,6 +159,11 @@
         return PatriciaTrieReadingUtils::hasShortcutTargets(mFlags);
     }
 
+    AK_FORCE_INLINE bool representsNonWordInfo() const {
+        return getCodePointCount() > 0 && CharUtils::isInUnicodeSpace(getCodePoints()[0])
+                && isNotAWord();
+    }
+
     // Parent node position
     AK_FORCE_INLINE int getParentPos() const {
         return mParentPos;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.cpp
index b3af1f4..30dcfba 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v2/patricia_trie_policy.cpp
@@ -24,6 +24,7 @@
 #include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_reading_helper.h"
 #include "suggest/policyimpl/dictionary/structure/pt_common/patricia_trie_reading_utils.h"
 #include "suggest/policyimpl/dictionary/utils/probability_utils.h"
+#include "utils/char_utils.h"
 
 namespace latinime {
 
@@ -318,12 +319,15 @@
     PatriciaTrieReadingUtils::readPtNodeInfo(mDictRoot, ptNodePos, getShortcutsStructurePolicy(),
             getBigramsStructurePolicy(), &flags, &mergedNodeCodePointCount, mergedNodeCodePoints,
             &probability, &childrenPos, &shortcutPos, &bigramPos, &siblingPos);
-    childDicNodes->pushLeavingChild(dicNode, ptNodePos, childrenPos, probability,
-            PatriciaTrieReadingUtils::isTerminal(flags),
-            PatriciaTrieReadingUtils::hasChildrenInFlags(flags),
-            PatriciaTrieReadingUtils::isBlacklisted(flags)
-                    || PatriciaTrieReadingUtils::isNotAWord(flags),
-            mergedNodeCodePointCount, mergedNodeCodePoints);
+    // Skip PtNodes don't start with Unicode code point because they represent non-word information.
+    if (CharUtils::isInUnicodeSpace(mergedNodeCodePoints[0])) {
+        childDicNodes->pushLeavingChild(dicNode, ptNodePos, childrenPos, probability,
+                PatriciaTrieReadingUtils::isTerminal(flags),
+                PatriciaTrieReadingUtils::hasChildrenInFlags(flags),
+                PatriciaTrieReadingUtils::isBlacklisted(flags)
+                        || PatriciaTrieReadingUtils::isNotAWord(flags),
+                mergedNodeCodePointCount, mergedNodeCodePoints);
+    }
     return siblingPos;
 }
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp
index 77ed38b..5aa6b9a 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.cpp
@@ -56,6 +56,7 @@
             return false;
         }
     }
+    umask(S_IWGRP | S_IWOTH);
     if (mkdir(tmpDirPath, S_IRWXU) == -1) {
         AKLOGE("Cannot create directory: %s. errno: %d.", tmpDirPath, errno);
         return false;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
index 2fb3dec..8373dc5 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_policy.cpp
@@ -59,13 +59,17 @@
             // valid terminal DicNode.
             isTerminal = ptNodeParams.getProbability() != NOT_A_PROBABILITY;
         }
+        readingHelper.readNextSiblingNode(ptNodeParams);
+        if (!ptNodeParams.representsNonWordInfo()) {
+            // Skip PtNodes that represent non-word information.
+            continue;
+        }
         childDicNodes->pushLeavingChild(dicNode, ptNodeParams.getHeadPos(),
                 ptNodeParams.getChildrenPos(), ptNodeParams.getProbability(), isTerminal,
                 ptNodeParams.hasChildren(),
                 ptNodeParams.isBlacklisted()
                         || ptNodeParams.isNotAWord() /* isBlacklistedOrNotAWord */,
                 ptNodeParams.getCodePointCount(), ptNodeParams.getCodePoints());
-        readingHelper.readNextSiblingNode(ptNodeParams);
     }
     if (readingHelper.isError()) {
         mIsCorrupted = true;
diff --git a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.cpp b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.cpp
index f31c502..e868ddf 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/structure/v4/ver4_patricia_trie_writing_helper.cpp
@@ -213,13 +213,16 @@
     // Delete unigrams.
     while (static_cast<int>(priorityQueue.size()) > maxUnigramCount) {
         const int ptNodePos = priorityQueue.top().getDictPos();
+        priorityQueue.pop();
         const PtNodeParams ptNodeParams =
                 ptNodeReader->fetchNodeInfoInBufferFromPtNodePos(ptNodePos);
+        if (ptNodeParams.representsNonWordInfo()) {
+            continue;
+        }
         if (!ptNodeWriter->markPtNodeAsWillBecomeNonTerminal(&ptNodeParams)) {
             AKLOGE("Cannot mark PtNode as willBecomeNonterminal. PtNode pos: %d", ptNodePos);
             return false;
         }
-        priorityQueue.pop();
     }
     return true;
 }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.cpp b/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.cpp
index 7bc7b0a..105363d 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.cpp
@@ -17,8 +17,13 @@
 #include "suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h"
 
 #include <cstdio>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
 
 #include "suggest/policyimpl/dictionary/header/header_policy.h"
+#include "suggest/policyimpl/dictionary/structure/backward/v401/ver4_dict_buffers.h"
 #include "suggest/policyimpl/dictionary/structure/pt_common/dynamic_pt_writing_utils.h"
 #include "suggest/policyimpl/dictionary/structure/v4/ver4_dict_buffers.h"
 #include "suggest/policyimpl/dictionary/utils/buffer_with_extendable_buffer.h"
@@ -36,10 +41,16 @@
     TimeKeeper::setCurrentTime();
     const FormatUtils::FORMAT_VERSION formatVersion = FormatUtils::getFormatVersion(dictVersion);
     switch (formatVersion) {
-        case FormatUtils::VERSION_4_ONLY_FOR_TESTING:
         case FormatUtils::VERSION_4:
-            return createEmptyV4DictFile(filePath, localeAsCodePointVector, attributeMap,
-                    formatVersion);
+            return createEmptyV4DictFile<backward::v401::Ver4DictConstants,
+                    backward::v401::Ver4DictBuffers,
+                    backward::v401::Ver4DictBuffers::Ver4DictBuffersPtr>(
+                            filePath, localeAsCodePointVector, attributeMap, formatVersion);
+        case FormatUtils::VERSION_4_ONLY_FOR_TESTING:
+        case FormatUtils::VERSION_4_DEV:
+            return createEmptyV4DictFile<Ver4DictConstants, Ver4DictBuffers,
+                    Ver4DictBuffers::Ver4DictBuffersPtr>(
+                            filePath, localeAsCodePointVector, attributeMap, formatVersion);
         default:
             AKLOGE("Cannot create dictionary %s because format version %d is not supported.",
                     filePath, dictVersion);
@@ -47,14 +58,14 @@
     }
 }
 
+template<class DictConstants, class DictBuffers, class DictBuffersPtr>
 /* static */ bool DictFileWritingUtils::createEmptyV4DictFile(const char *const dirPath,
         const std::vector<int> localeAsCodePointVector,
         const DictionaryHeaderStructurePolicy::AttributeMap *const attributeMap,
         const FormatUtils::FORMAT_VERSION formatVersion) {
     HeaderPolicy headerPolicy(formatVersion, localeAsCodePointVector, attributeMap);
-    Ver4DictBuffers::Ver4DictBuffersPtr dictBuffers(
-            Ver4DictBuffers::createVer4DictBuffers(&headerPolicy,
-                    Ver4DictConstants::MAX_DICT_EXTENDED_REGION_SIZE));
+    DictBuffersPtr dictBuffers = DictBuffers::createVer4DictBuffers(&headerPolicy,
+            DictConstants::MAX_DICT_EXTENDED_REGION_SIZE);
     headerPolicy.fillInAndWriteHeaderToBuffer(true /* updatesLastDecayedTime */,
             0 /* unigramCount */, 0 /* bigramCount */,
             0 /* extendedRegionSize */, dictBuffers->getWritableHeaderBuffer());
@@ -100,9 +111,15 @@
 
 /* static */ bool DictFileWritingUtils::flushBufferToFile(const char *const filePath,
         const BufferWithExtendableBuffer *const buffer) {
-    FILE *const file = fopen(filePath, "wb");
+    const int fd = open(filePath, O_WRONLY | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR);
+    if (fd == -1) {
+        AKLOGE("File %s cannot be opened. errno: %d", filePath, errno);
+        ASSERT(false);
+        return false;
+    }
+    FILE *const file = fdopen(fd, "wb");
     if (!file) {
-        AKLOGE("File %s cannot be opened.", filePath);
+        AKLOGE("fdopen failed for the file %s. errno: %d", filePath, errno);
         ASSERT(false);
         return false;
     }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h b/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h
index a822989..5df5856 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/utils/dict_file_writing_utils.h
@@ -45,6 +45,12 @@
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(DictFileWritingUtils);
 
+    static bool createEmptyV401DictFile(const char *const filePath,
+            const std::vector<int> localeAsCodePointVector,
+            const DictionaryHeaderStructurePolicy::AttributeMap *const attributeMap,
+            const FormatUtils::FORMAT_VERSION formatVersion);
+
+    template<class DictConstants, class DictBuffers, class DictBuffersPtr>
     static bool createEmptyV4DictFile(const char *const filePath,
             const std::vector<int> localeAsCodePointVector,
             const DictionaryHeaderStructurePolicy::AttributeMap *const attributeMap,
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.cpp b/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.cpp
index a8518cd..ba405b0 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.cpp
@@ -33,6 +33,8 @@
             return VERSION_4_ONLY_FOR_TESTING;
         case VERSION_4:
             return VERSION_4;
+        case VERSION_4_DEV:
+            return VERSION_4_DEV;
         default:
             return UNKNOWN_VERSION;
     }
@@ -62,6 +64,8 @@
                 return VERSION_4_ONLY_FOR_TESTING;
             } else if (ByteArrayUtils::readUint16(dict, 4) == VERSION_4) {
                 return VERSION_4;
+            } else if (ByteArrayUtils::readUint16(dict, 4) == VERSION_4_DEV) {
+                return VERSION_4_DEV;
             } else {
                 return UNKNOWN_VERSION;
             }
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.h b/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.h
index 20dfb9d..c47f30c 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.h
+++ b/native/jni/src/suggest/policyimpl/dictionary/utils/format_utils.h
@@ -33,6 +33,7 @@
         VERSION_2 = 2,
         VERSION_4_ONLY_FOR_TESTING = 399,
         VERSION_4 = 401,
+        VERSION_4_DEV = 402,
         UNKNOWN_VERSION = -1
     };
 
diff --git a/native/jni/src/suggest/policyimpl/dictionary/utils/mmapped_buffer.cpp b/native/jni/src/suggest/policyimpl/dictionary/utils/mmapped_buffer.cpp
index d3e0c23..4a126ff 100644
--- a/native/jni/src/suggest/policyimpl/dictionary/utils/mmapped_buffer.cpp
+++ b/native/jni/src/suggest/policyimpl/dictionary/utils/mmapped_buffer.cpp
@@ -33,7 +33,7 @@
     const int mmapFd = open(path, O_RDONLY);
     if (mmapFd < 0) {
         AKLOGE("DICT: Can't open the source. path=%s errno=%d", path, errno);
-        return MmappedBufferPtr(nullptr);
+        return nullptr;
     }
     const int pagesize = sysconf(_SC_PAGESIZE);
     const int offset = bufferOffset % pagesize;
@@ -45,13 +45,13 @@
     if (mmappedBuffer == MAP_FAILED) {
         AKLOGE("DICT: Can't mmap dictionary. errno=%d", errno);
         close(mmapFd);
-        return MmappedBufferPtr(nullptr);
+        return nullptr;
     }
     uint8_t *const buffer = static_cast<uint8_t *>(mmappedBuffer) + offset;
     if (!buffer) {
         AKLOGE("DICT: buffer is null");
         close(mmapFd);
-        return MmappedBufferPtr(nullptr);
+        return nullptr;
     }
     return MmappedBufferPtr(new MmappedBuffer(buffer, bufferSize, mmappedBuffer, alignedSize,
             mmapFd, isUpdatable));
@@ -61,7 +61,7 @@
         const char *const path, const bool isUpdatable) {
     const int fileSize = FileUtils::getFileSize(path);
     if (fileSize == -1) {
-        return MmappedBufferPtr(nullptr);
+        return nullptr;
     } else if (fileSize == 0) {
         return MmappedBufferPtr(new MmappedBuffer(isUpdatable));
     } else {
@@ -76,7 +76,7 @@
     const int filePathLength = snprintf(filePath, filePathBufferSize, "%s%s", dirPath,
             fileName);
     if (filePathLength >= filePathBufferSize) {
-        return MmappedBufferPtr(nullptr);
+        return nullptr;
     }
     return openBuffer(filePath, isUpdatable);
 }
diff --git a/native/jni/src/utils/char_utils.cpp b/native/jni/src/utils/char_utils.cpp
index adc474b..b17e084 100644
--- a/native/jni/src/utils/char_utils.cpp
+++ b/native/jni/src/utils/char_utils.cpp
@@ -22,6 +22,9 @@
 
 namespace latinime {
 
+const int CharUtils::MIN_UNICODE_CODE_POINT = 0;
+const int CharUtils::MAX_UNICODE_CODE_POINT = 0x10FFFF;
+
 struct LatinCapitalSmallPair {
   unsigned short capital;
   unsigned short small;
diff --git a/native/jni/src/utils/char_utils.h b/native/jni/src/utils/char_utils.h
index 239419d..634c45b 100644
--- a/native/jni/src/utils/char_utils.h
+++ b/native/jni/src/utils/char_utils.h
@@ -86,12 +86,19 @@
         return spaceCount;
     }
 
+    static AK_FORCE_INLINE int isInUnicodeSpace(const int codePoint) {
+        return codePoint >= MIN_UNICODE_CODE_POINT && codePoint <= MAX_UNICODE_CODE_POINT;
+    }
+
     static unsigned short latin_tolower(const unsigned short c);
     static const std::vector<int> EMPTY_STRING;
 
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(CharUtils);
 
+    static const int MIN_UNICODE_CODE_POINT;
+    static const int MAX_UNICODE_CODE_POINT;
+
     /**
      * Table mapping most combined Latin, Greek, and Cyrillic characters
      * to their base characters.  If c is in range, BASE_CHARS[c] == c
diff --git a/native/jni/src/utils/jni_data_utils.cpp b/native/jni/src/utils/jni_data_utils.cpp
new file mode 100644
index 0000000..5555293
--- /dev/null
+++ b/native/jni/src/utils/jni_data_utils.cpp
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "utils/jni_data_utils.h"
+
+namespace latinime {
+
+const int JniDataUtils::CODE_POINT_REPLACEMENT_CHARACTER = 0xFFFD;
+const int JniDataUtils::CODE_POINT_NULL = 0;
+
+} // namespace latinime
diff --git a/native/jni/src/utils/jni_data_utils.h b/native/jni/src/utils/jni_data_utils.h
index 2ce02dc..67a66fd 100644
--- a/native/jni/src/utils/jni_data_utils.h
+++ b/native/jni/src/utils/jni_data_utils.h
@@ -23,6 +23,7 @@
 #include "jni.h"
 #include "suggest/core/policy/dictionary_header_structure_policy.h"
 #include "suggest/policyimpl/dictionary/header/header_read_write_utils.h"
+#include "utils/char_utils.h"
 
 namespace latinime {
 
@@ -65,8 +66,44 @@
         return attributeMap;
     }
 
+    static void outputCodePoints(JNIEnv *env, jintArray intArrayToOutputCodePoints, const int start,
+            const int maxLength, const int *const codePoints, const int codePointCount,
+            const bool needsNullTermination) {
+        const int outputCodePointCount = std::min(maxLength, codePointCount);
+        int outputCodePonts[outputCodePointCount];
+        for (int i = 0; i < outputCodePointCount; ++i) {
+            const int codePoint = codePoints[i];
+            if (!CharUtils::isInUnicodeSpace(codePoint)) {
+                outputCodePonts[i] = CODE_POINT_REPLACEMENT_CHARACTER;
+            } else if (codePoint >= 0x01 && codePoint <= 0x1F) {
+                // Control code.
+                outputCodePonts[i] = CODE_POINT_REPLACEMENT_CHARACTER;
+            } else {
+                outputCodePonts[i] = codePoint;
+            }
+        }
+        env->SetIntArrayRegion(intArrayToOutputCodePoints, start, outputCodePointCount,
+                outputCodePonts);
+        if (needsNullTermination && outputCodePointCount < maxLength) {
+            env->SetIntArrayRegion(intArrayToOutputCodePoints, start + outputCodePointCount,
+                    1 /* len */, &CODE_POINT_NULL);
+        }
+    }
+
+    static void putIntToArray(JNIEnv *env, jintArray array, const int index, const int value) {
+        env->SetIntArrayRegion(array, index, 1 /* len */, &value);
+    }
+
+    static void putFloatToArray(JNIEnv *env, jfloatArray array, const int index,
+            const float value) {
+        env->SetFloatArrayRegion(array, index, 1 /* len */, &value);
+    }
+
  private:
     DISALLOW_IMPLICIT_CONSTRUCTORS(JniDataUtils);
+
+    static const int CODE_POINT_REPLACEMENT_CHARACTER;
+    static const int CODE_POINT_NULL;
 };
 } // namespace latinime
 #endif // LATINIME_JNI_DATA_UTILS_H
diff --git a/tests/src/com/android/inputmethod/keyboard/KeyboardThemeTests.java b/tests/src/com/android/inputmethod/keyboard/KeyboardThemeTests.java
index 9b532fe..555b1a4 100644
--- a/tests/src/com/android/inputmethod/keyboard/KeyboardThemeTests.java
+++ b/tests/src/com/android/inputmethod/keyboard/KeyboardThemeTests.java
@@ -29,7 +29,7 @@
     private static final int THEME_ID_NULL = -1;
     private static final int THEME_ID_ICS = KeyboardTheme.THEME_ID_ICS;
     private static final int THEME_ID_KLP = KeyboardTheme.THEME_ID_KLP;
-    private static final int THEME_ID_LMP = KeyboardTheme.THEME_ID_LMP;
+    private static final int THEME_ID_LXX = KeyboardTheme.THEME_ID_LXX;
 
     @Override
     protected void setUp() throws Exception {
@@ -64,11 +64,11 @@
         assertDefaultKeyboardTheme(sdkVersion, THEME_ID_KLP, THEME_ID_KLP);
     }
 
-    private void assertDefaultKeyboardThemeLMP(final int sdkVersion) {
-        // Forced to switch to LMP theme.
-        assertDefaultKeyboardTheme(sdkVersion, THEME_ID_NULL, THEME_ID_LMP);
-        assertDefaultKeyboardTheme(sdkVersion, THEME_ID_ICS, THEME_ID_LMP);
-        assertDefaultKeyboardTheme(sdkVersion, THEME_ID_KLP, THEME_ID_LMP);
+    private void assertDefaultKeyboardThemeLXX(final int sdkVersion) {
+        // Forced to switch to LXX theme.
+        assertDefaultKeyboardTheme(sdkVersion, THEME_ID_NULL, THEME_ID_LXX);
+        assertDefaultKeyboardTheme(sdkVersion, THEME_ID_ICS, THEME_ID_LXX);
+        assertDefaultKeyboardTheme(sdkVersion, THEME_ID_KLP, THEME_ID_LXX);
     }
 
     public void testDefaultKeyboardThemeICS() {
@@ -86,8 +86,8 @@
         assertDefaultKeyboardThemeKLP(VERSION_CODES.KITKAT);
     }
 
-    public void testDefaultKeyboardThemeLMP() {
+    public void testDefaultKeyboardThemeLXX() {
         // TODO: Update this constant once the *next* version becomes available.
-        assertDefaultKeyboardThemeLMP(VERSION_CODES.CUR_DEVELOPMENT);
+        assertDefaultKeyboardThemeLXX(VERSION_CODES.CUR_DEVELOPMENT);
     }
 }
diff --git a/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java b/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java
index 35d9a4e..90b90ff 100644
--- a/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java
+++ b/tests/src/com/android/inputmethod/latin/BinaryDictionaryDecayingTests.java
@@ -46,6 +46,8 @@
     private static final String TEST_DICT_FILE_EXTENSION = ".testDict";
     private static final String TEST_LOCALE = "test";
     private static final int DUMMY_PROBABILITY = 0;
+    private static final int[] DICT_FORMAT_VERSIONS =
+            new int[] { FormatSpec.VERSION4, FormatSpec.VERSION4_DEV };
 
     private int mCurrentTime = 0;
 
@@ -94,7 +96,8 @@
     private File createEmptyDictionaryAndGetFile(final String dictId,
             final int formatVersion) throws IOException {
         if (formatVersion == FormatSpec.VERSION4
-                || formatVersion == FormatSpec.VERSION4_ONLY_FOR_TESTING) {
+                || formatVersion == FormatSpec.VERSION4_ONLY_FOR_TESTING
+                || formatVersion == FormatSpec.VERSION4_DEV) {
             return createEmptyVer4DictionaryAndGetFile(dictId, formatVersion);
         } else {
             throw new IOException("Dictionary format version " + formatVersion
@@ -120,7 +123,7 @@
             return file;
         } else {
             throw new IOException("Empty dictionary " + file.getAbsolutePath()
-                    + " cannot be created.");
+                    + " cannot be created. Foramt version: " + formatVersion);
         }
     }
 
@@ -133,7 +136,9 @@
     }
 
     public void testReadDictInJavaSide() {
-        testReadDictInJavaSide(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testReadDictInJavaSide(formatVersion);
+        }
     }
 
     private void testReadDictInJavaSide(final int formatVersion) {
@@ -178,10 +183,6 @@
     }
 
     public void testControlCurrentTime() {
-        testControlCurrentTime(FormatSpec.VERSION4);
-    }
-
-    private void testControlCurrentTime(final int formatVersion) {
         final int TEST_COUNT = 1000;
         final long seed = System.currentTimeMillis();
         final Random random = new Random(seed);
@@ -197,7 +198,9 @@
     }
 
     public void testAddValidAndInvalidWords() {
-        testAddValidAndInvalidWords(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testAddValidAndInvalidWords(formatVersion);
+        }
     }
 
     private void testAddValidAndInvalidWords(final int formatVersion) {
@@ -240,7 +243,9 @@
     }
 
     public void testDecayingProbability() {
-        testDecayingProbability(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testDecayingProbability(formatVersion);
+        }
     }
 
     private void testDecayingProbability(final int formatVersion) {
@@ -295,7 +300,9 @@
     }
 
     public void testAddManyUnigramsToDecayingDict() {
-        testAddManyUnigramsToDecayingDict(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testAddManyUnigramsToDecayingDict(formatVersion);
+        }
     }
 
     private void testAddManyUnigramsToDecayingDict(final int formatVersion) {
@@ -354,7 +361,9 @@
     }
 
     public void testOverflowUnigrams() {
-        testOverflowUnigrams(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testOverflowUnigrams(formatVersion);
+        }
     }
 
     private void testOverflowUnigrams(final int formatVersion) {
@@ -413,7 +422,9 @@
     }
 
     public void testAddManyBigramsToDecayingDict() {
-        testAddManyBigramsToDecayingDict(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testAddManyBigramsToDecayingDict(formatVersion);
+        }
     }
 
     private void testAddManyBigramsToDecayingDict(final int formatVersion) {
@@ -487,7 +498,9 @@
     }
 
     public void testOverflowBigrams() {
-        testOverflowBigrams(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testOverflowBigrams(formatVersion);
+        }
     }
 
     private void testOverflowBigrams(final int formatVersion) {
@@ -566,7 +579,9 @@
     }
 
     public void testDictMigration() {
-        testDictMigration(FormatSpec.VERSION4_ONLY_FOR_TESTING, FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testDictMigration(FormatSpec.VERSION4_ONLY_FOR_TESTING, formatVersion);
+        }
     }
 
     private void testDictMigration(final int fromFormatVersion, final int toFormatVersion) {
diff --git a/tests/src/com/android/inputmethod/latin/BinaryDictionaryTests.java b/tests/src/com/android/inputmethod/latin/BinaryDictionaryTests.java
index 770e76e..cfeed0a 100644
--- a/tests/src/com/android/inputmethod/latin/BinaryDictionaryTests.java
+++ b/tests/src/com/android/inputmethod/latin/BinaryDictionaryTests.java
@@ -43,11 +43,14 @@
 public class BinaryDictionaryTests extends AndroidTestCase {
     private static final String TEST_DICT_FILE_EXTENSION = ".testDict";
     private static final String TEST_LOCALE = "test";
+    private static final int[] DICT_FORMAT_VERSIONS =
+            new int[] { FormatSpec.VERSION4, FormatSpec.VERSION4_DEV };
 
     private File createEmptyDictionaryAndGetFile(final String dictId,
             final int formatVersion) throws IOException {
         if (formatVersion == FormatSpec.VERSION4
-                || formatVersion == FormatSpec.VERSION4_ONLY_FOR_TESTING) {
+                || formatVersion == FormatSpec.VERSION4_ONLY_FOR_TESTING
+                || formatVersion == FormatSpec.VERSION4_DEV) {
             return createEmptyVer4DictionaryAndGetFile(dictId, formatVersion);
         } else {
             throw new IOException("Dictionary format version " + formatVersion
@@ -67,12 +70,14 @@
             return file;
         } else {
             throw new IOException("Empty dictionary " + file.getAbsolutePath()
-                    + " cannot be created.");
+                    + " cannot be created. Format version: " + formatVersion);
         }
     }
 
     public void testIsValidDictionary() {
-        testIsValidDictionary(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testIsValidDictionary(formatVersion);
+        }
     }
 
     private void testIsValidDictionary(final int formatVersion) {
@@ -100,7 +105,9 @@
     }
 
     public void testConstructingDictionaryOnMemory() {
-        testConstructingDictionaryOnMemory(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testConstructingDictionaryOnMemory(formatVersion);
+        }
     }
 
     private void testConstructingDictionaryOnMemory(final int formatVersion) {
@@ -131,7 +138,9 @@
     }
 
     public void testAddTooLongWord() {
-        testAddTooLongWord(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testAddTooLongWord(formatVersion);
+        }
     }
 
     private void testAddTooLongWord(final int formatVersion) {
@@ -190,7 +199,9 @@
     }
 
     public void testAddUnigramWord() {
-        testAddUnigramWord(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testAddUnigramWord(formatVersion);
+        }
     }
 
     private void testAddUnigramWord(final int formatVersion) {
@@ -232,7 +243,9 @@
     }
 
     public void testRandomlyAddUnigramWord() {
-        testRandomlyAddUnigramWord(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testRandomlyAddUnigramWord(formatVersion);
+        }
     }
 
     private void testRandomlyAddUnigramWord(final int formatVersion) {
@@ -268,7 +281,9 @@
     }
 
     public void testAddBigramWords() {
-        testAddBigramWords(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testAddBigramWords(formatVersion);
+        }
     }
 
     private void testAddBigramWords(final int formatVersion) {
@@ -336,7 +351,9 @@
     }
 
     public void testRandomlyAddBigramWords() {
-        testRandomlyAddBigramWords(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testRandomlyAddBigramWords(formatVersion);
+        }
     }
 
     private void testRandomlyAddBigramWords(final int formatVersion) {
@@ -397,7 +414,9 @@
     }
 
     public void testRemoveBigramWords() {
-        testRemoveBigramWords(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testRemoveBigramWords(formatVersion);
+        }
     }
 
     private void testRemoveBigramWords(final int formatVersion) {
@@ -447,7 +466,9 @@
     }
 
     public void testFlushDictionary() {
-        testFlushDictionary(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testFlushDictionary(formatVersion);
+        }
     }
 
     private void testFlushDictionary(final int formatVersion) {
@@ -499,7 +520,9 @@
     }
 
     public void testFlushWithGCDictionary() {
-        testFlushWithGCDictionary(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testFlushWithGCDictionary(formatVersion);
+        }
     }
 
     private void testFlushWithGCDictionary(final int formatVersion) {
@@ -547,7 +570,9 @@
     }
 
     public void testAddBigramWordsAndFlashWithGC() {
-        testAddBigramWordsAndFlashWithGC(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testAddBigramWordsAndFlashWithGC(formatVersion);
+        }
     }
 
     // TODO: Evaluate performance of GC
@@ -616,7 +641,9 @@
     }
 
     public void testRandomOperationsAndFlashWithGC() {
-        testRandomOperationsAndFlashWithGC(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testRandomOperationsAndFlashWithGC(formatVersion);
+        }
     }
 
     private void testRandomOperationsAndFlashWithGC(final int formatVersion) {
@@ -727,7 +754,9 @@
     }
 
     public void testAddManyUnigramsAndFlushWithGC() {
-        testAddManyUnigramsAndFlushWithGC(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testAddManyUnigramsAndFlushWithGC(formatVersion);
+        }
     }
 
     private void testAddManyUnigramsAndFlushWithGC(final int formatVersion) {
@@ -775,7 +804,9 @@
     }
 
     public void testUnigramAndBigramCount() {
-        testUnigramAndBigramCount(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testUnigramAndBigramCount(formatVersion);
+        }
     }
 
     private void testUnigramAndBigramCount(final int formatVersion) {
@@ -834,7 +865,9 @@
     }
 
     public void testAddMultipleDictionaryEntries() {
-        testAddMultipleDictionaryEntries(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testAddMultipleDictionaryEntries(formatVersion);
+        }
     }
 
     private void testAddMultipleDictionaryEntries(final int formatVersion) {
@@ -896,7 +929,9 @@
     }
 
     public void testGetWordProperties() {
-        testGetWordProperties(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testGetWordProperties(formatVersion);
+        }
     }
 
     private void testGetWordProperties(final int formatVersion) {
@@ -995,7 +1030,9 @@
     }
 
     public void testIterateAllWords() {
-        testIterateAllWords(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testIterateAllWords(formatVersion);
+        }
     }
 
     private void testIterateAllWords(final int formatVersion) {
@@ -1091,7 +1128,9 @@
     }
 
     public void testAddShortcuts() {
-        testAddShortcuts(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testAddShortcuts(formatVersion);
+        }
     }
 
     private void testAddShortcuts(final int formatVersion) {
@@ -1151,7 +1190,9 @@
     }
 
     public void testAddManyShortcuts() {
-        testAddManyShortcuts(FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testAddManyShortcuts(formatVersion);
+        }
     }
 
     private void testAddManyShortcuts(final int formatVersion) {
@@ -1227,7 +1268,9 @@
     }
 
     public void testDictMigration() {
-        testDictMigration(FormatSpec.VERSION4_ONLY_FOR_TESTING, FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testDictMigration(FormatSpec.VERSION4_ONLY_FOR_TESTING, formatVersion);
+        }
     }
 
     private void testDictMigration(final int fromFormatVersion, final int toFormatVersion) {
@@ -1271,7 +1314,9 @@
     }
 
     public void testLargeDictMigration() {
-        testLargeDictMigration(FormatSpec.VERSION4_ONLY_FOR_TESTING, FormatSpec.VERSION4);
+        for (final int formatVersion : DICT_FORMAT_VERSIONS) {
+            testLargeDictMigration(FormatSpec.VERSION4_ONLY_FOR_TESTING, formatVersion);
+        }
     }
 
     private void testLargeDictMigration(final int fromFormatVersion, final int toFormatVersion) {
diff --git a/tests/src/com/android/inputmethod/latin/InputLogicTests.java b/tests/src/com/android/inputmethod/latin/InputLogicTests.java
index 29423e8..a944416 100644
--- a/tests/src/com/android/inputmethod/latin/InputLogicTests.java
+++ b/tests/src/com/android/inputmethod/latin/InputLogicTests.java
@@ -600,4 +600,16 @@
         assertEquals("type words letter by letter", EXPECTED_RESULT,
                 mEditText.getText().toString());
     }
+
+    public void testSwitchLanguages() {
+        final String WORD_TO_TYPE_FIRST_PART = "com";
+        final String WORD_TO_TYPE_SECOND_PART = "md ";
+        final String EXPECTED_RESULT = "comme ";
+        changeLanguage("en");
+        type(WORD_TO_TYPE_FIRST_PART);
+        changeLanguage("fr");
+        type(WORD_TO_TYPE_SECOND_PART);
+        assertEquals("Composing continues after switching languages", EXPECTED_RESULT,
+                mEditText.getText().toString());
+    }
 }
diff --git a/tests/src/com/android/inputmethod/latin/InputLogicTestsReorderingMyanmar.java b/tests/src/com/android/inputmethod/latin/InputLogicTestsReorderingMyanmar.java
index b3f2819..bb36a2a 100644
--- a/tests/src/com/android/inputmethod/latin/InputLogicTestsReorderingMyanmar.java
+++ b/tests/src/com/android/inputmethod/latin/InputLogicTestsReorderingMyanmar.java
@@ -220,7 +220,7 @@
 
     public void testMyanmarReordering() {
         int testNumber = 0;
-        changeLanguage("mm_MY");
+        changeLanguage("my_MM", "CombiningRules=MyanmarReordering");
         for (final Pair[] test : TESTS) {
             // Small trick to reset LatinIME : setText("") and send updateSelection with values
             // LatinIME has never seen, and cursor pos 0,0.
diff --git a/tests/src/com/android/inputmethod/latin/InputTestsBase.java b/tests/src/com/android/inputmethod/latin/InputTestsBase.java
index 260e534..09c5320 100644
--- a/tests/src/com/android/inputmethod/latin/InputTestsBase.java
+++ b/tests/src/com/android/inputmethod/latin/InputTestsBase.java
@@ -299,11 +299,15 @@
     }
 
     protected void changeLanguage(final String locale) {
-        changeLanguageWithoutWait(locale);
+        changeLanguage(locale, null);
+    }
+
+    protected void changeLanguage(final String locale, final String combiningSpec) {
+        changeLanguageWithoutWait(locale, combiningSpec);
         waitForDictionariesToBeLoaded();
     }
 
-    protected void changeLanguageWithoutWait(final String locale) {
+    protected void changeLanguageWithoutWait(final String locale, final String combiningSpec) {
         mEditText.mCurrentLocale = LocaleUtils.constructLocaleFromString(locale);
         // TODO: this is forcing a QWERTY keyboard for all locales, which is wrong.
         // It's still better than using whatever keyboard is the current one, but we
@@ -314,7 +318,8 @@
                 "KeyboardLayoutSet=" + SubtypeLocaleUtils.QWERTY
                 + "," + Constants.Subtype.ExtraValue.ASCII_CAPABLE
                 + "," + Constants.Subtype.ExtraValue.ENABLED_WHEN_DEFAULT_IS_NOT_ASCII_CAPABLE
-                + "," + Constants.Subtype.ExtraValue.EMOJI_CAPABLE;
+                + "," + Constants.Subtype.ExtraValue.EMOJI_CAPABLE
+                + null == combiningSpec ? "" : ("," + combiningSpec);
         final InputMethodSubtype subtype = InputMethodSubtypeCompatUtils.newInputMethodSubtype(
                 R.string.subtype_no_language_qwerty,
                 R.drawable.ic_ime_switcher_dark,
@@ -325,7 +330,7 @@
                 false /* overridesImplicitlyEnabledSubtype */,
                 0 /* id */);
         SubtypeSwitcher.getInstance().forceSubtype(subtype);
-        mLatinIME.loadKeyboard();
+        mLatinIME.onCurrentInputMethodSubtypeChanged(subtype);
         runMessages();
         mKeyboard = mLatinIME.mKeyboardSwitcher.getKeyboard();
         mLatinIME.clearPersonalizedDictionariesForTest();
diff --git a/tests/src/com/android/inputmethod/latin/LatinImeStressTests.java b/tests/src/com/android/inputmethod/latin/LatinImeStressTests.java
index db14b83..0a29d83 100644
--- a/tests/src/com/android/inputmethod/latin/LatinImeStressTests.java
+++ b/tests/src/com/android/inputmethod/latin/LatinImeStressTests.java
@@ -33,7 +33,8 @@
         final int codePointSetSize = 30;
         final int[] codePointSet = CodePointUtils.LATIN_ALPHABETS_LOWER;
         for (int i = 0; i < switchCount; ++i) {
-            changeLanguageWithoutWait(locales[random.nextInt(locales.length)]);
+            changeLanguageWithoutWait(locales[random.nextInt(locales.length)],
+                    null /* combiningSpec */);
             final int wordCount = random.nextInt(maxWordCountToTypeInEachIteration);
             for (int j = 0; j < wordCount; ++j) {
                 final String word = CodePointUtils.generateWord(random, codePointSet);
@@ -50,7 +51,8 @@
         final int codePointSetSize = 30;
         final int[] codePointSet = CodePointUtils.generateCodePointSet(codePointSetSize, random);
         for (int i = 0; i < switchCount; ++i) {
-            changeLanguageWithoutWait(locales[random.nextInt(locales.length)]);
+            changeLanguageWithoutWait(locales[random.nextInt(locales.length)],
+                    null /* combiningSpec */);
             final int wordCount = random.nextInt(maxWordCountToTypeInEachIteration);
             for (int j = 0; j < wordCount; ++j) {
                 final String word = CodePointUtils.generateWord(random, codePointSet);
diff --git a/tools/dicttool/compat/com/android/inputmethod/event/CombinerChain.java b/tools/dicttool/compat/com/android/inputmethod/event/CombinerChain.java
index 47f781e..538d759 100644
--- a/tools/dicttool/compat/com/android/inputmethod/event/CombinerChain.java
+++ b/tools/dicttool/compat/com/android/inputmethod/event/CombinerChain.java
@@ -28,8 +28,10 @@
 // TODO: there should not be a dependency to this in dicttool, so there
 // should be a sensible way to separate them cleanly.
 public class CombinerChain {
-    private StringBuilder mComposingWord = new StringBuilder();
-    public CombinerChain(final Combiner... combinerList) {}
+    private StringBuilder mComposingWord;
+    public CombinerChain(final String initialText, final Combiner... combinerList) {
+        mComposingWord = new StringBuilder(initialText);
+    }
 
     public void processEvent(final ArrayList<Event> previousEvents, final Event newEvent) {
         mComposingWord.append(newEvent.getTextToCommit());