diff --git a/java/src/com/android/inputmethod/latin/LatinIME.java b/java/src/com/android/inputmethod/latin/LatinIME.java
index 6a10131..0f7263d 100644
--- a/java/src/com/android/inputmethod/latin/LatinIME.java
+++ b/java/src/com/android/inputmethod/latin/LatinIME.java
@@ -100,7 +100,6 @@
 import com.android.inputmethod.latin.utils.StringUtils;
 import com.android.inputmethod.latin.utils.TargetPackageInfoGetterTask;
 import com.android.inputmethod.latin.utils.TextRange;
-import com.android.inputmethod.latin.utils.UserHistoryForgettingCurveUtils;
 import com.android.inputmethod.research.ResearchLogger;
 
 import java.io.FileDescriptor;
@@ -1019,11 +1018,6 @@
             // Only for debug
             mBoostPersonalizationDictionaryForDebug =
                     currentSettingsValues.mBoostPersonalizationDictionaryForDebug;
-            if (mBoostPersonalizationDictionaryForDebug) {
-                UserHistoryForgettingCurveUtils.boostMaxFreqForDebug();
-            } else {
-                UserHistoryForgettingCurveUtils.resetMaxFreqForDebug();
-            }
         }
     }
 
diff --git a/java/src/com/android/inputmethod/latin/utils/UserHistoryForgettingCurveUtils.java b/java/src/com/android/inputmethod/latin/utils/UserHistoryForgettingCurveUtils.java
deleted file mode 100644
index 677035e..0000000
--- a/java/src/com/android/inputmethod/latin/utils/UserHistoryForgettingCurveUtils.java
+++ /dev/null
@@ -1,242 +0,0 @@
-/*
- * Copyright (C) 2012 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 android.util.Log;
-
-import java.util.concurrent.TimeUnit;
-
-import com.android.inputmethod.annotations.UsedForTesting;
-
-@UsedForTesting
-public final class UserHistoryForgettingCurveUtils {
-    private static final String TAG = UserHistoryForgettingCurveUtils.class.getSimpleName();
-    private static final boolean DEBUG = false;
-    private static final int DEFAULT_FC_FREQ = 127;
-    private static final int BOOSTED_FC_FREQ = 200;
-    private static int FC_FREQ_MAX = DEFAULT_FC_FREQ;
-    /* package */ static final int COUNT_MAX = 3;
-    private static final int FC_LEVEL_MAX = 3;
-    /* package */ static final int ELAPSED_TIME_MAX = 15;
-    private static final int ELAPSED_TIME_INTERVAL_HOURS = 6;
-    private static final long ELAPSED_TIME_INTERVAL_MILLIS =
-            TimeUnit.HOURS.toMillis(ELAPSED_TIME_INTERVAL_HOURS);
-    private static final int HALF_LIFE_HOURS = 48;
-    private static final int MAX_PUSH_ELAPSED = (FC_LEVEL_MAX + 1) * (ELAPSED_TIME_MAX + 1);
-
-    public static void boostMaxFreqForDebug() {
-        FC_FREQ_MAX = BOOSTED_FC_FREQ;
-    }
-
-    public static void resetMaxFreqForDebug() {
-        FC_FREQ_MAX = DEFAULT_FC_FREQ;
-    }
-
-    private UserHistoryForgettingCurveUtils() {
-        // This utility class is not publicly instantiable.
-    }
-
-    public static final class ForgettingCurveParams {
-        private byte mFc;
-        long mLastTouchedTime = 0;
-        private final boolean mIsValid;
-
-        private void updateLastTouchedTime() {
-            mLastTouchedTime = System.currentTimeMillis();
-        }
-
-        public ForgettingCurveParams(boolean isValid) {
-            this(System.currentTimeMillis(), isValid);
-        }
-
-        private ForgettingCurveParams(long now, boolean isValid) {
-            this(pushCount((byte)0, isValid), now, now, isValid);
-        }
-
-        /** This constructor is called when the user history bigram dictionary is being restored. */
-        public ForgettingCurveParams(int fc, long now, long last) {
-            // All words with level >= 1 had been saved.
-            // Invalid words with level == 0 had been saved.
-            // Valid words words with level == 0 had *not* been saved.
-            this(fc, now, last, fcToLevel((byte)fc) > 0);
-        }
-
-        private ForgettingCurveParams(int fc, long now, long last, boolean isValid) {
-            mIsValid = isValid;
-            mFc = (byte)fc;
-            mLastTouchedTime = last;
-            updateElapsedTime(now);
-        }
-
-        public boolean isValid() {
-            return mIsValid;
-        }
-
-        public byte getFc() {
-            updateElapsedTime(System.currentTimeMillis());
-            return mFc;
-        }
-
-        public int getFrequency() {
-            updateElapsedTime(System.currentTimeMillis());
-            return UserHistoryForgettingCurveUtils.fcToFreq(mFc);
-        }
-
-        public int notifyTypedAgainAndGetFrequency() {
-            updateLastTouchedTime();
-            // TODO: Check whether this word is valid or not
-            mFc = pushCount(mFc, false);
-            return UserHistoryForgettingCurveUtils.fcToFreq(mFc);
-        }
-
-        private void updateElapsedTime(long now) {
-            final int elapsedTimeCount =
-                    (int)((now - mLastTouchedTime) / ELAPSED_TIME_INTERVAL_MILLIS);
-            if (elapsedTimeCount <= 0) {
-                return;
-            }
-            if (elapsedTimeCount >= MAX_PUSH_ELAPSED) {
-                mLastTouchedTime = now;
-                mFc = 0;
-                return;
-            }
-            for (int i = 0; i < elapsedTimeCount; ++i) {
-                mLastTouchedTime += ELAPSED_TIME_INTERVAL_MILLIS;
-                mFc = pushElapsedTime(mFc);
-            }
-        }
-    }
-
-    @UsedForTesting
-    /* package */ static  int fcToElapsedTime(byte fc) {
-        return fc & 0x0F;
-    }
-
-    @UsedForTesting
-    /* package */ static int fcToCount(byte fc) {
-        return (fc >> 4) & 0x03;
-    }
-
-    @UsedForTesting
-    /* package */ static int fcToLevel(byte fc) {
-        return (fc >> 6) & 0x03;
-    }
-
-    @UsedForTesting
-    private static int calcFreq(int elapsedTime, int count, int level) {
-        if (level <= 0) {
-            // Reserved words, just return -1
-            return -1;
-        }
-        if (count == COUNT_MAX) {
-            // Temporary promote because it's frequently typed recently
-            ++level;
-        }
-        final int et = Math.min(FC_FREQ_MAX, Math.max(0, elapsedTime));
-        final int l = Math.min(FC_LEVEL_MAX, Math.max(0, level));
-        return MathUtils.SCORE_TABLE[l - 1][et];
-    }
-
-    /* pakcage */ static byte calcFc(int elapsedTime, int count, int level) {
-        final int et = Math.min(FC_FREQ_MAX, Math.max(0, elapsedTime));
-        final int c = Math.min(COUNT_MAX, Math.max(0, count));
-        final int l = Math.min(FC_LEVEL_MAX, Math.max(0, level));
-        return (byte)(et | (c << 4) | (l << 6));
-    }
-
-    public static int fcToFreq(byte fc) {
-        final int elapsedTime = fcToElapsedTime(fc);
-        final int count = fcToCount(fc);
-        final int level = fcToLevel(fc);
-        return calcFreq(elapsedTime, count, level);
-    }
-
-    @UsedForTesting
-    public static byte pushElapsedTime(byte fc) {
-        int elapsedTime = fcToElapsedTime(fc);
-        int count = fcToCount(fc);
-        int level = fcToLevel(fc);
-        if (elapsedTime >= ELAPSED_TIME_MAX) {
-            // Downgrade level
-            elapsedTime = 0;
-            count = COUNT_MAX;
-            --level;
-        } else {
-            ++elapsedTime;
-        }
-        return calcFc(elapsedTime, count, level);
-    }
-
-    @UsedForTesting
-    public static byte pushCount(byte fc, boolean isValid) {
-        final int elapsedTime = fcToElapsedTime(fc);
-        int count = fcToCount(fc);
-        int level = fcToLevel(fc);
-        if ((elapsedTime == 0 && count >= COUNT_MAX) || (isValid && level == 0)) {
-            // Upgrade level
-            ++level;
-            count = 0;
-            if (DEBUG) {
-                Log.d(TAG, "Upgrade level.");
-            }
-        } else {
-            ++count;
-        }
-        return calcFc(0, count, level);
-    }
-
-    // TODO: isValid should be false for a word whose frequency is 0,
-    // or that is not in the dictionary.
-    /**
-     * Check wheather we should save the bigram to the SQL DB or not
-     */
-    public static boolean needsToSave(byte fc, boolean isValid, boolean addLevel0Bigram) {
-        int level = fcToLevel(fc);
-        if (level == 0) {
-            if (isValid || !addLevel0Bigram) {
-                return false;
-            }
-        }
-        final int elapsedTime = fcToElapsedTime(fc);
-        return (elapsedTime < ELAPSED_TIME_MAX - 1 || level > 0);
-    }
-
-    private static final class MathUtils {
-        public static final int[][] SCORE_TABLE = new int[FC_LEVEL_MAX][ELAPSED_TIME_MAX + 1];
-        static {
-            for (int i = 0; i < FC_LEVEL_MAX; ++i) {
-                final float initialFreq;
-                if (i >= 2) {
-                    initialFreq = FC_FREQ_MAX;
-                } else if (i == 1) {
-                    initialFreq = FC_FREQ_MAX / 2;
-                } else if (i == 0) {
-                    initialFreq = FC_FREQ_MAX / 4;
-                } else {
-                    continue;
-                }
-                for (int j = 0; j < ELAPSED_TIME_MAX; ++j) {
-                    final float elapsedHours = j * ELAPSED_TIME_INTERVAL_HOURS;
-                    final float freq = initialFreq
-                            * (float)Math.pow(initialFreq, elapsedHours / HALF_LIFE_HOURS);
-                    final int intFreq = Math.min(FC_FREQ_MAX, Math.max(0, (int)freq));
-                    SCORE_TABLE[i][j] = intFreq;
-                }
-            }
-        }
-    }
-}
diff --git a/tests/src/com/android/inputmethod/latin/utils/ForgettingCurveTests.java b/tests/src/com/android/inputmethod/latin/utils/ForgettingCurveTests.java
deleted file mode 100644
index 823bd5d..0000000
--- a/tests/src/com/android/inputmethod/latin/utils/ForgettingCurveTests.java
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- * Copyright (C) 2012 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 android.test.AndroidTestCase;
-import android.test.suitebuilder.annotation.SmallTest;
-
-@SmallTest
-public class ForgettingCurveTests extends AndroidTestCase {
-    public void testFcToFreq() {
-        for (int i = 0; i < Byte.MAX_VALUE; ++i) {
-            final byte fc = (byte)i;
-            final int e = UserHistoryForgettingCurveUtils.fcToElapsedTime(fc);
-            final int c = UserHistoryForgettingCurveUtils.fcToCount(fc);
-            final int l = UserHistoryForgettingCurveUtils.fcToLevel(fc);
-            final byte fc2 = UserHistoryForgettingCurveUtils.calcFc(e, c, l);
-            assertEquals(fc, fc2);
-        }
-        byte fc = 0;
-        int l;
-        for (int i = 0; i < 4; ++i) {
-            for (int j = 0; j < (UserHistoryForgettingCurveUtils.COUNT_MAX + 1); ++j) {
-                fc = UserHistoryForgettingCurveUtils.pushCount(fc, true);
-            }
-            l = UserHistoryForgettingCurveUtils.fcToLevel(fc);
-            assertEquals(l, Math.max(1, Math.min(i + 1, 3)));
-        }
-        fc = 0;
-        for (int i = 0; i < 4; ++i) {
-            for (int j = 0; j < (UserHistoryForgettingCurveUtils.COUNT_MAX + 1); ++j) {
-                fc = UserHistoryForgettingCurveUtils.pushCount(fc, false);
-            }
-            l = UserHistoryForgettingCurveUtils.fcToLevel(fc);
-            assertEquals(l, Math.min(i + 1, 3));
-        }
-        for (int i = 0; i < 4; ++i) {
-            for (int j = 0; j < (UserHistoryForgettingCurveUtils.ELAPSED_TIME_MAX + 1); ++j) {
-                fc = UserHistoryForgettingCurveUtils.pushElapsedTime(fc);
-            }
-            l = UserHistoryForgettingCurveUtils.fcToLevel(fc);
-            assertEquals(l, Math.max(0, 2 - i));
-        }
-    }
-}