diff --git a/res/layout/notif_importance_preference.xml b/res/layout/notif_importance_preference.xml
index 29c337a..44c135b 100644
--- a/res/layout/notif_importance_preference.xml
+++ b/res/layout/notif_importance_preference.xml
@@ -99,7 +99,7 @@
         <TextView
             android:id="@+id/silence_summary"
             android:paddingTop="@dimen/notification_importance_button_padding"
-            android:text="@string/notification_channel_summary_default"
+            android:text="@string/notification_channel_summary_low"
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
             android:clickable="false"
diff --git a/res/values/strings.xml b/res/values/strings.xml
index 161f816..f1acce7 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -7032,6 +7032,8 @@
     <string name="help_uri_wifi_scanning_required" translatable="false"></string>
     <!-- url for the bluetooth toggle required dialog help page -->
     <string name="help_uri_bluetooth_screen" translatable="false"></string>
+    <!-- url for the SIM combination warning required dialog help page -->
+    <string name="help_uri_sim_combination_warning" translatable="false"></string>
 
     <!-- User account title [CHAR LIMIT=30] -->
     <string name="user_account_title">Account for content</string>
@@ -11288,4 +11290,12 @@
 
     <!-- Title for enable MMS notification channel.  [CHAR LIMIT=40] -->
     <string name="enable_mms_notification_channel_title">MMS message</string>
+
+    <!-- Title for SIM combination warning. [CHAR LIMIT=80] -->
+    <string name="sim_combination_warning_notification_title">Issue with SIM combination</string>
+    <!-- Message for DSDS dual CDMA SIM combination warning. [CHAR LIMIT=100] -->
+    <string name="dual_cdma_sim_warning_notification_summary">Using <xliff:g id="operator_names" example="T-Mobile &amp; Verizon">%1$s</xliff:g> may limit functionality. Tap to learn more.</string>
+
+    <!-- Title for enable MMS notification channel.  [CHAR LIMIT=40] -->
+    <string name="dual_cdma_sim_warning_notification_channel_title">SIM combination</string>
 </resources>
diff --git a/src/com/android/settings/applications/appinfo/ExternalSourcesDetails.java b/src/com/android/settings/applications/appinfo/ExternalSourcesDetails.java
index b723274..fe1d81c 100644
--- a/src/com/android/settings/applications/appinfo/ExternalSourcesDetails.java
+++ b/src/com/android/settings/applications/appinfo/ExternalSourcesDetails.java
@@ -18,6 +18,7 @@
 import static android.app.Activity.RESULT_CANCELED;
 import static android.app.Activity.RESULT_OK;
 
+import android.app.ActivityManager;
 import android.app.AppOpsManager;
 import android.app.settings.SettingsEnums;
 import android.content.Context;
@@ -29,6 +30,7 @@
 import androidx.preference.Preference;
 import androidx.preference.Preference.OnPreferenceChangeListener;
 
+import com.android.internal.annotations.VisibleForTesting;
 import com.android.settings.R;
 import com.android.settings.Settings;
 import com.android.settings.applications.AppInfoWithHeader;
@@ -44,6 +46,7 @@
 
     private AppStateInstallAppsBridge mAppBridge;
     private AppOpsManager mAppOpsManager;
+    private ActivityManager mActivityManager;
     private UserManager mUserManager;
     private RestrictedSwitchPreference mSwitchPref;
     private InstallAppsState mInstallAppsState;
@@ -55,6 +58,7 @@
         final Context context = getActivity();
         mAppBridge = new AppStateInstallAppsBridge(context, mState, null);
         mAppOpsManager = (AppOpsManager) context.getSystemService(Context.APP_OPS_SERVICE);
+        mActivityManager = context.getSystemService(ActivityManager.class);
         mUserManager = UserManager.get(context);
 
         addPreferencesFromResource(R.xml.external_sources_details);
@@ -99,10 +103,21 @@
                 : R.string.app_permission_summary_not_allowed);
     }
 
-    private void setCanInstallApps(boolean newState) {
+    @VisibleForTesting
+    void setCanInstallApps(boolean newState) {
         mAppOpsManager.setMode(AppOpsManager.OP_REQUEST_INSTALL_PACKAGES,
                 mPackageInfo.applicationInfo.uid, mPackageName,
                 newState ? AppOpsManager.MODE_ALLOWED : AppOpsManager.MODE_ERRORED);
+        if (!newState) {
+            killApp(mPackageInfo.applicationInfo.uid);
+        }
+    }
+
+    private void killApp(int uid) {
+        if (UserHandle.isCore(uid)) {
+            return;
+        }
+        mActivityManager.killUid(uid, "User denied OP_REQUEST_INSTALL_PACKAGES");
     }
 
     @Override
diff --git a/src/com/android/settings/notification/ImportancePreference.java b/src/com/android/settings/notification/ImportancePreference.java
index 3e81d0c..b059f91 100644
--- a/src/com/android/settings/notification/ImportancePreference.java
+++ b/src/com/android/settings/notification/ImportancePreference.java
@@ -27,6 +27,7 @@
 import android.content.res.ColorStateList;
 import android.graphics.drawable.Drawable;
 import android.transition.AutoTransition;
+import android.transition.Transition;
 import android.transition.TransitionManager;
 import android.util.AttributeSet;
 import android.view.View;
@@ -112,6 +113,7 @@
             mAlertButton.setEnabled(false);
         }
 
+        setImportanceSummary((ViewGroup) holder.itemView, mImportance, false);
         switch (mImportance) {
             case IMPORTANCE_MIN:
             case IMPORTANCE_LOW:
@@ -126,23 +128,29 @@
                 mAlertButton.setSelected(true);
                 break;
         }
-        setImportanceSummary((ViewGroup) holder.itemView, mImportance, false);
 
         mSilenceButton.setOnClickListener(v -> {
             callChangeListener(IMPORTANCE_LOW);
             mAlertButton.setBackground(unselectedBackground);
-            mAlertButton.setSelected(false);
             mSilenceButton.setBackground(selectedBackground);
-            mSilenceButton.setSelected(true);
             setImportanceSummary((ViewGroup) holder.itemView, IMPORTANCE_LOW, true);
+            // a11y service won't always read the newly appearing text in the right order if the
+            // selection happens too soon (readback happens on a different thread as layout). post
+            // the selection to make that conflict less likely
+            holder.itemView.post(() -> {
+                mAlertButton.setSelected(false);
+                mSilenceButton.setSelected(true);
+            });
         });
         mAlertButton.setOnClickListener(v -> {
             callChangeListener(IMPORTANCE_DEFAULT);
             mSilenceButton.setBackground(unselectedBackground);
-            mSilenceButton.setSelected(false);
             mAlertButton.setBackground(selectedBackground);
-            mAlertButton.setSelected(true);
             setImportanceSummary((ViewGroup) holder.itemView, IMPORTANCE_DEFAULT, true);
+            holder.itemView.post(() -> {
+                mSilenceButton.setSelected(false);
+                mAlertButton.setSelected(true);
+            });
         });
     }
 
@@ -172,9 +180,7 @@
             ((ImageView) parent.findViewById(R.id.alert_icon)).setImageTintList(colorAccent);
             ((TextView) parent.findViewById(R.id.alert_label)).setTextColor(colorAccent);
 
-            TextView view = parent.findViewById(R.id.alert_summary);
-            view.setText(R.string.notification_channel_summary_default);
-            view.setVisibility(VISIBLE);
+            parent.findViewById(R.id.alert_summary).setVisibility(VISIBLE);
         } else {
             parent.findViewById(R.id.alert_summary).setVisibility(GONE);
             ((ImageView) parent.findViewById(R.id.alert_icon)).setImageTintList(colorNormal);
@@ -182,9 +188,7 @@
 
             ((ImageView) parent.findViewById(R.id.silence_icon)).setImageTintList(colorAccent);
             ((TextView) parent.findViewById(R.id.silence_label)).setTextColor(colorAccent);
-            TextView view = parent.findViewById(R.id.silence_summary);
-            view.setVisibility(VISIBLE);
-            view.setText(R.string.notification_channel_summary_low);
+            parent.findViewById(R.id.silence_summary).setVisibility(VISIBLE);
         }
     }
 }
diff --git a/src/com/android/settings/sim/SimSelectNotification.java b/src/com/android/settings/sim/SimSelectNotification.java
index d228b6e..a303e42 100644
--- a/src/com/android/settings/sim/SimSelectNotification.java
+++ b/src/com/android/settings/sim/SimSelectNotification.java
@@ -24,6 +24,10 @@
 import static android.telephony.TelephonyManager.EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE_ALL;
 import static android.telephony.TelephonyManager.EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE_DATA;
 import static android.telephony.TelephonyManager.EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE_NONE;
+import static android.telephony.TelephonyManager.EXTRA_SIM_COMBINATION_NAMES;
+import static android.telephony.TelephonyManager.EXTRA_SIM_COMBINATION_WARNING_TYPE;
+import static android.telephony.TelephonyManager.EXTRA_SIM_COMBINATION_WARNING_TYPE_DUAL_CDMA;
+import static android.telephony.TelephonyManager.EXTRA_SIM_COMBINATION_WARNING_TYPE_NONE;
 import static android.telephony.TelephonyManager.EXTRA_SUBSCRIPTION_ID;
 import static android.telephony.data.ApnSetting.TYPE_MMS;
 
@@ -43,6 +47,7 @@
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.settings.R;
 import com.android.settings.network.telephony.MobileNetworkActivity;
+import com.android.settingslib.HelpUtils;
 
 public class SimSelectNotification extends BroadcastReceiver {
     private static final String TAG = "SimSelectNotification";
@@ -50,6 +55,8 @@
     public static final int SIM_SELECT_NOTIFICATION_ID = 1;
     @VisibleForTesting
     public static final int ENABLE_MMS_NOTIFICATION_ID = 2;
+    @VisibleForTesting
+    public static final int SIM_WARNING_NOTIFICATION_ID = 3;
 
     @VisibleForTesting
     public static final String SIM_SELECT_NOTIFICATION_CHANNEL =
@@ -59,6 +66,10 @@
     public static final String ENABLE_MMS_NOTIFICATION_CHANNEL =
             "enable_mms_notification_channel";
 
+    @VisibleForTesting
+    public static final String SIM_WARNING_NOTIFICATION_CHANNEL =
+            "sim_warning_notification_channel";
+
     @Override
     public void onReceive(Context context, Intent intent) {
         String action = intent.getAction();
@@ -125,13 +136,23 @@
     }
 
     private void onPrimarySubscriptionListChanged(Context context, Intent intent) {
+        startSimSelectDialogIfNeeded(context, intent);
+        sendSimCombinationWarningIfNeeded(context, intent);
+    }
+
+    private void startSimSelectDialogIfNeeded(Context context, Intent intent) {
+        int dialogType = intent.getIntExtra(EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE,
+                EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE_NONE);
+
+        if (dialogType == EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE_NONE) {
+            return;
+        }
+
         // Cancel any previous notifications
         cancelSimSelectNotification(context);
         // Create a notification to tell the user that some defaults are missing
         createSimSelectNotification(context);
 
-        int dialogType = intent.getIntExtra(EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE,
-                EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE_NONE);
         if (dialogType == EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE_ALL) {
             int subId = intent.getIntExtra(EXTRA_SUBSCRIPTION_ID,
                     SubscriptionManager.DEFAULT_SUBSCRIPTION_ID);
@@ -139,11 +160,12 @@
             // If there is only one subscription, ask if user wants to use if for everything
             Intent newIntent = new Intent(context, SimDialogActivity.class);
             newIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
-            newIntent.putExtra(SimDialogActivity.DIALOG_TYPE_KEY, SimDialogActivity.PREFERRED_PICK);
+            newIntent.putExtra(SimDialogActivity.DIALOG_TYPE_KEY,
+                    SimDialogActivity.PREFERRED_PICK);
             newIntent.putExtra(SimDialogActivity.PREFERRED_SIM, slotIndex);
             context.startActivity(newIntent);
         } else if (dialogType == EXTRA_DEFAULT_SUBSCRIPTION_SELECT_TYPE_DATA) {
-            // If there are mulitple, ensure they pick default data
+            // If there are multiple, ensure they pick default data
             Intent newIntent = new Intent(context, SimDialogActivity.class);
             newIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
             newIntent.putExtra(SimDialogActivity.DIALOG_TYPE_KEY, SimDialogActivity.DATA_PICK);
@@ -151,6 +173,18 @@
         }
     }
 
+    private void sendSimCombinationWarningIfNeeded(Context context, Intent intent) {
+        final int warningType = intent.getIntExtra(EXTRA_SIM_COMBINATION_WARNING_TYPE,
+                EXTRA_SIM_COMBINATION_WARNING_TYPE_NONE);
+
+        if (warningType == EXTRA_SIM_COMBINATION_WARNING_TYPE_DUAL_CDMA) {
+            // Cancel any previous notifications
+            cancelSimCombinationWarningNotification(context);
+            // Create a notification to tell the user that some defaults are missing
+            createSimCombinationWarningNotification(context, intent);
+        }
+    }
+
     private void createSimSelectNotification(Context context){
         final Resources resources = context.getResources();
 
@@ -222,4 +256,52 @@
                 (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
         notificationManager.cancel(ENABLE_MMS_NOTIFICATION_ID);
     }
+
+    private void createSimCombinationWarningNotification(Context context, Intent intent){
+        final Resources resources = context.getResources();
+        final String simNames = intent.getStringExtra(EXTRA_SIM_COMBINATION_NAMES);
+
+        if (simNames == null) {
+            return;
+        }
+
+        CharSequence dualCdmaSimWarningSummary = resources.getString(
+                R.string.dual_cdma_sim_warning_notification_summary, simNames);
+
+        NotificationChannel notificationChannel = new NotificationChannel(
+                SIM_WARNING_NOTIFICATION_CHANNEL,
+                resources.getText(R.string.dual_cdma_sim_warning_notification_channel_title),
+                NotificationManager.IMPORTANCE_HIGH);
+
+        Notification.Builder builder =
+                new Notification.Builder(context, SIM_WARNING_NOTIFICATION_CHANNEL)
+                        .setSmallIcon(R.drawable.ic_sim_card_alert_white_48dp)
+                        .setColor(context.getColor(R.color.sim_noitification))
+                        .setContentTitle(resources.getText(
+                                R.string.sim_combination_warning_notification_title))
+                        .setContentText(dualCdmaSimWarningSummary)
+                        .setStyle(new Notification.BigTextStyle().bigText(
+                                dualCdmaSimWarningSummary))
+                        .setAutoCancel(true);
+
+        // Create the pending intent that will lead to the helper page.
+        Intent resultIntent = HelpUtils.getHelpIntent(
+                context,
+                context.getString(R.string.help_uri_sim_combination_warning),
+                context.getClass().getName());
+        PendingIntent resultPendingIntent = PendingIntent.getActivity(context, 0, resultIntent,
+                PendingIntent.FLAG_CANCEL_CURRENT);
+        builder.setContentIntent(resultPendingIntent);
+
+        NotificationManager notificationManager =
+                context.getSystemService(NotificationManager.class);
+        notificationManager.createNotificationChannel(notificationChannel);
+        notificationManager.notify(SIM_WARNING_NOTIFICATION_ID, builder.build());
+    }
+
+    public static void cancelSimCombinationWarningNotification(Context context) {
+        NotificationManager notificationManager =
+                context.getSystemService(NotificationManager.class);
+        notificationManager.cancel(SIM_WARNING_NOTIFICATION_ID);
+    }
 }
diff --git a/tests/robotests/src/com/android/settings/applications/appinfo/ExternalSourcesDetailsTest.java b/tests/robotests/src/com/android/settings/applications/appinfo/ExternalSourcesDetailsTest.java
index 10c2675..002a0bc 100644
--- a/tests/robotests/src/com/android/settings/applications/appinfo/ExternalSourcesDetailsTest.java
+++ b/tests/robotests/src/com/android/settings/applications/appinfo/ExternalSourcesDetailsTest.java
@@ -19,11 +19,17 @@
 import static com.google.common.truth.Truth.assertThat;
 
 import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.ArgumentMatchers.nullable;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
+import android.app.ActivityManager;
+import android.app.AppOpsManager;
 import android.content.Context;
 import android.content.ContextWrapper;
 import android.content.pm.ApplicationInfo;
@@ -55,6 +61,10 @@
     @Mock
     private UserManager mUserManager;
     @Mock
+    private ActivityManager mActivityManager;
+    @Mock
+    private AppOpsManager mAppOpsManager;
+    @Mock
     private RestrictedSwitchPreference mSwitchPref;
     @Mock
     private RestrictedPreferenceHelper mHelper;
@@ -69,10 +79,47 @@
 
         mFragment = new ExternalSourcesDetails();
         ReflectionHelpers.setField(mFragment, "mUserManager", mUserManager);
+        ReflectionHelpers.setField(mFragment, "mActivityManager", mActivityManager);
+        ReflectionHelpers.setField(mFragment, "mAppOpsManager", mAppOpsManager);
         ReflectionHelpers.setField(mFragment, "mSwitchPref", mSwitchPref);
     }
 
     @Test
+    public void setCanInstallApps_false_shouldKillNonCoreUid() {
+        int mockUid = 23456;
+        ReflectionHelpers.setField(mFragment, "mPackageInfo", mPackageInfo);
+
+        mPackageInfo.applicationInfo = new ApplicationInfo();
+        mPackageInfo.applicationInfo.uid = mockUid;
+        assertThat(UserHandle.isCore(mockUid)).isFalse();
+        mFragment.setCanInstallApps(false);
+        verify(mActivityManager).killUid(eq(mockUid), anyString());
+    }
+
+    @Test
+    public void setCanInstallApps_false_shouldNotKillCoreUid() {
+        int mockUid = 1234;
+        ReflectionHelpers.setField(mFragment, "mPackageInfo", mPackageInfo);
+
+        mPackageInfo.applicationInfo = new ApplicationInfo();
+        mPackageInfo.applicationInfo.uid = mockUid;
+        assertThat(UserHandle.isCore(mockUid)).isTrue();
+        mFragment.setCanInstallApps(false);
+        verify(mActivityManager, never()).killUid(eq(mockUid), anyString());
+    }
+
+    @Test
+    public void setCanInstallApps_true_shouldNotKillUid() {
+        int mockUid = 23456;
+        ReflectionHelpers.setField(mFragment, "mPackageInfo", mPackageInfo);
+
+        mPackageInfo.applicationInfo = new ApplicationInfo();
+        mPackageInfo.applicationInfo.uid = mockUid;
+        mFragment.setCanInstallApps(true);
+        verify(mActivityManager, never()).killUid(eq(mockUid), anyString());
+    }
+
+    @Test
     public void refreshUi_noPackageInfo_shouldReturnFalseAndNoCrash() {
         mFragment.refreshUi();
 
diff --git a/tests/robotests/src/com/android/settings/sim/SimSelectNotificationTest.java b/tests/robotests/src/com/android/settings/sim/SimSelectNotificationTest.java
index 69c0919..5a2dd48 100644
--- a/tests/robotests/src/com/android/settings/sim/SimSelectNotificationTest.java
+++ b/tests/robotests/src/com/android/settings/sim/SimSelectNotificationTest.java
@@ -21,10 +21,15 @@
 import static android.provider.Settings.ENABLE_MMS_DATA_REQUEST_REASON_OUTGOING_MMS;
 import static android.provider.Settings.EXTRA_ENABLE_MMS_DATA_REQUEST_REASON;
 import static android.provider.Settings.EXTRA_SUB_ID;
+import static android.telephony.TelephonyManager.EXTRA_SIM_COMBINATION_NAMES;
+import static android.telephony.TelephonyManager.EXTRA_SIM_COMBINATION_WARNING_TYPE;
+import static android.telephony.TelephonyManager.EXTRA_SIM_COMBINATION_WARNING_TYPE_DUAL_CDMA;
 import static android.telephony.data.ApnSetting.TYPE_MMS;
 
 import static com.android.settings.sim.SimSelectNotification.ENABLE_MMS_NOTIFICATION_CHANNEL;
 import static com.android.settings.sim.SimSelectNotification.ENABLE_MMS_NOTIFICATION_ID;
+import static com.android.settings.sim.SimSelectNotification.SIM_WARNING_NOTIFICATION_CHANNEL;
+import static com.android.settings.sim.SimSelectNotification.SIM_WARNING_NOTIFICATION_ID;
 
 import static com.google.common.truth.Truth.assertThat;
 
@@ -76,10 +81,16 @@
     @Mock
     private Resources mResources;
 
-    private String mFakeOperatorName = "fake_operator_name";
-    private CharSequence mFakeNotificationChannelTitle = "fake_notification_channel_title";
-    private CharSequence mFakeNotificationTitle = "fake_notification_title";
-    private String mFakeNotificationSummary = "fake_notification_Summary";
+    private final String mFakeOperatorName = "fake_operator_name";
+    private final CharSequence mFakeNotificationChannelTitle = "fake_notification_channel_title";
+    private final CharSequence mFakeNotificationTitle = "fake_notification_title";
+    private final String mFakeNotificationSummary = "fake_notification_Summary";
+
+    // Dual CDMA combination notification.
+    private final String mFakeDualCdmaWarningChannelTitle = "fake_dual_cdma_warning_channel_title";
+    private final String mFakeDualCdmaWarningTitle = "fake_dual_cdma_warning_title";
+    private final String mFakeDualCdmaWarningSummary = "fake_dual_cdma_warning_summary";
+    private final String mSimCombinationName = " carrier1 & carrier 2";
 
     private int mSubId = 1;
 
@@ -90,6 +101,8 @@
         MockitoAnnotations.initMocks(this);
         when(mContext.getSystemService(Context.NOTIFICATION_SERVICE))
                 .thenReturn(mNotificationManager);
+        when(mContext.getSystemService(NotificationManager.class))
+                .thenReturn(mNotificationManager);
         when(mContext.getSystemService(Context.TELEPHONY_SERVICE))
                 .thenReturn(mTelephonyManager);
         when(mContext.getSystemService(Context.TELEPHONY_SUBSCRIPTION_SERVICE))
@@ -111,6 +124,13 @@
                 .thenReturn(mFakeNotificationChannelTitle);
         when(mResources.getString(R.string.enable_mms_notification_summary,
                 mFakeOperatorName)).thenReturn(mFakeNotificationSummary);
+
+        when(mResources.getText(R.string.dual_cdma_sim_warning_notification_channel_title))
+                .thenReturn(mFakeDualCdmaWarningChannelTitle);
+        when(mResources.getText(R.string.sim_combination_warning_notification_title))
+                .thenReturn(mFakeDualCdmaWarningTitle);
+        when(mResources.getString(R.string.dual_cdma_sim_warning_notification_summary,
+                mSimCombinationName)).thenReturn(mFakeDualCdmaWarningSummary);
     }
 
     @Test
@@ -162,5 +182,43 @@
         mSimSelectNotification.onReceive(mContext, intent);
         verify(mNotificationManager, never()).createNotificationChannel(any());
     }
+
+    @Test
+    public void onReceivePrimarySubListChange_NoExtra_notificationShouldNotSend() {
+        Intent intent = new Intent(TelephonyManager.ACTION_PRIMARY_SUBSCRIPTION_LIST_CHANGED);
+
+        // EXTRA_SUB_ID and EXTRA_ENABLE_MMS_DATA_REQUEST_REASON are required.
+        mSimSelectNotification.onReceive(mContext, intent);
+        verify(mNotificationManager, never()).createNotificationChannel(any());
+    }
+
+    @Test
+    public void onReceivePrimarySubListChange_DualCdmaWarning_notificationShouldSend() {
+        Intent intent = new Intent(TelephonyManager.ACTION_PRIMARY_SUBSCRIPTION_LIST_CHANGED);
+
+        intent.putExtra(EXTRA_SIM_COMBINATION_NAMES, mSimCombinationName);
+        intent.putExtra(EXTRA_SIM_COMBINATION_WARNING_TYPE,
+                EXTRA_SIM_COMBINATION_WARNING_TYPE_DUAL_CDMA);
+
+        mSimSelectNotification.onReceive(mContext, intent);
+
+        // Capture the notification channel created and verify its fields.
+        ArgumentCaptor<NotificationChannel> nc = ArgumentCaptor.forClass(NotificationChannel.class);
+        verify(mNotificationManager).createNotificationChannel(nc.capture());
+
+        assertThat(nc.getValue().getId()).isEqualTo(SIM_WARNING_NOTIFICATION_CHANNEL);
+        assertThat(nc.getValue().getName()).isEqualTo(mFakeDualCdmaWarningChannelTitle);
+        assertThat(nc.getValue().getImportance()).isEqualTo(IMPORTANCE_HIGH);
+
+        // Capture the notification it notifies and verify its fields.
+        ArgumentCaptor<Notification> notification = ArgumentCaptor.forClass(Notification.class);
+        verify(mNotificationManager).notify(
+                eq(SIM_WARNING_NOTIFICATION_ID), notification.capture());
+        assertThat(notification.getValue().extras.getCharSequence(Notification.EXTRA_TITLE))
+                .isEqualTo(mFakeDualCdmaWarningTitle);
+        assertThat(notification.getValue().extras.getCharSequence(Notification.EXTRA_BIG_TEXT))
+                .isEqualTo(mFakeDualCdmaWarningSummary);
+        assertThat(notification.getValue().contentIntent).isNotNull();
+    }
 }