diff --git a/core/java/android/app/INotificationManager.aidl b/core/java/android/app/INotificationManager.aidl
index cc7e0fd0fd397..1c1883b3b7f50 100644
--- a/core/java/android/app/INotificationManager.aidl
+++ b/core/java/android/app/INotificationManager.aidl
@@ -71,6 +71,7 @@ interface INotificationManager
     int getDeletedChannelCount(String pkg, int uid);
     void deleteNotificationChannelGroup(String pkg, String channelGroupId);
     ParceledListSlice getNotificationChannelGroups(String pkg);
+    boolean onlyHasDefaultChannel(String pkg, int uid);
 
     // TODO: Remove this when callers have been migrated to the equivalent
     // INotificationListener method.
diff --git a/services/core/java/com/android/server/notification/NotificationManagerService.java b/services/core/java/com/android/server/notification/NotificationManagerService.java
index 6cf54c89651ce..9cd0dff539912 100644
--- a/services/core/java/com/android/server/notification/NotificationManagerService.java
+++ b/services/core/java/com/android/server/notification/NotificationManagerService.java
@@ -1826,6 +1826,12 @@ public class NotificationManagerService extends SystemService {
                     .getList().size();
         }
 
+        @Override
+        public boolean onlyHasDefaultChannel(String pkg, int uid) {
+            enforceSystemOrSystemUI("onlyHasDefaultChannel");
+            return mRankingHelper.onlyHasDefaultChannel(pkg, uid);
+        }
+
         @Override
         public int getDeletedChannelCount(String pkg, int uid) {
             enforceSystemOrSystemUI("getDeletedChannelCount");
diff --git a/services/core/java/com/android/server/notification/RankingHelper.java b/services/core/java/com/android/server/notification/RankingHelper.java
index 2c51510de6895..e83d453d1938f 100644
--- a/services/core/java/com/android/server/notification/RankingHelper.java
+++ b/services/core/java/com/android/server/notification/RankingHelper.java
@@ -312,7 +312,8 @@ public class RankingHelper implements RankingConfig {
 
     private void createDefaultChannelIfNeeded(Record r) throws NameNotFoundException {
         if (r.channels.containsKey(NotificationChannel.DEFAULT_CHANNEL_ID)) {
-            // Already exists
+            r.channels.get(NotificationChannel.DEFAULT_CHANNEL_ID).setName(
+                    mContext.getString(R.string.default_notification_channel_label));
             return;
         }
 
@@ -778,6 +779,21 @@ public class RankingHelper implements RankingConfig {
         return new ParceledListSlice<>(channels);
     }
 
+    /**
+     * True for pre-O apps that only have the default channel, or pre O apps that have no
+     * channels yet. This method will create the default channel for pre-O apps that don't have it.
+     * Should never be true for O+ targeting apps, but that's enforced on boot/when an app
+     * upgrades.
+     */
+    public boolean onlyHasDefaultChannel(String pkg, int uid) {
+        Record r = getOrCreateRecord(pkg, uid);
+        if (r.channels.size() == 1
+                && r.channels.containsKey(NotificationChannel.DEFAULT_CHANNEL_ID)) {
+            return true;
+        }
+        return false;
+    }
+
     public int getDeletedChannelCount(String pkg, int uid) {
         Preconditions.checkNotNull(pkg);
         int deletedCount = 0;
diff --git a/services/tests/notification/src/com/android/server/notification/RankingHelperTest.java b/services/tests/notification/src/com/android/server/notification/RankingHelperTest.java
index b7f51864331c4..0f8c815bb2a2e 100644
--- a/services/tests/notification/src/com/android/server/notification/RankingHelperTest.java
+++ b/services/tests/notification/src/com/android/server/notification/RankingHelperTest.java
@@ -872,6 +872,15 @@ public class RankingHelperTest extends NotificationTestCase {
                 mHelper.getNotificationChannel(PKG, UID, newChannel.getId(), false));
     }
 
+    @Test
+    public void testOnlyHasDefaultChannel() throws Exception {
+        assertTrue(mHelper.onlyHasDefaultChannel(PKG, UID));
+        assertFalse(mHelper.onlyHasDefaultChannel(UPDATED_PKG, UID2));
+
+        mHelper.createNotificationChannel(PKG, UID, getChannel(), true);
+        assertFalse(mHelper.onlyHasDefaultChannel(PKG, UID));
+    }
+
     @Test
     public void testCreateChannel_defaultChannelId() throws Exception {
         try {