diff --git a/api/current.txt b/api/current.txt
index 3b2150dec3773..61b6e279e8d61 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -36771,6 +36771,7 @@ package android.telephony {
     field public static final java.lang.String KEY_ALLOW_EMERGENCY_NUMBERS_IN_CALL_LOG_BOOL = "allow_emergency_numbers_in_call_log_bool";
     field public static final java.lang.String KEY_ALLOW_EMERGENCY_VIDEO_CALLS_BOOL = "allow_emergency_video_calls_bool";
     field public static final java.lang.String KEY_ALLOW_LOCAL_DTMF_TONES_BOOL = "allow_local_dtmf_tones_bool";
+    field public static final java.lang.String KEY_ALLOW_MERGE_WIFI_CALLS_WHEN_VOWIFI_OFF_BOOL = "allow_merge_wifi_calls_when_vowifi_off_bool";
     field public static final java.lang.String KEY_ALLOW_NON_EMERGENCY_CALLS_IN_ECM_BOOL = "allow_non_emergency_calls_in_ecm_bool";
     field public static final java.lang.String KEY_ALWAYS_SHOW_EMERGENCY_ALERT_ONOFF_BOOL = "always_show_emergency_alert_onoff_bool";
     field public static final java.lang.String KEY_APN_EXPAND_BOOL = "apn_expand_bool";
diff --git a/api/system-current.txt b/api/system-current.txt
index 5d5f4136fe2ba..0cd5eade0b370 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -39810,6 +39810,7 @@ package android.telephony {
     field public static final java.lang.String KEY_ALLOW_EMERGENCY_NUMBERS_IN_CALL_LOG_BOOL = "allow_emergency_numbers_in_call_log_bool";
     field public static final java.lang.String KEY_ALLOW_EMERGENCY_VIDEO_CALLS_BOOL = "allow_emergency_video_calls_bool";
     field public static final java.lang.String KEY_ALLOW_LOCAL_DTMF_TONES_BOOL = "allow_local_dtmf_tones_bool";
+    field public static final java.lang.String KEY_ALLOW_MERGE_WIFI_CALLS_WHEN_VOWIFI_OFF_BOOL = "allow_merge_wifi_calls_when_vowifi_off_bool";
     field public static final java.lang.String KEY_ALLOW_NON_EMERGENCY_CALLS_IN_ECM_BOOL = "allow_non_emergency_calls_in_ecm_bool";
     field public static final java.lang.String KEY_ALWAYS_SHOW_EMERGENCY_ALERT_ONOFF_BOOL = "always_show_emergency_alert_onoff_bool";
     field public static final java.lang.String KEY_APN_EXPAND_BOOL = "apn_expand_bool";
diff --git a/api/test-current.txt b/api/test-current.txt
index 72d4bbaed727e..4199dd824eda4 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -36849,6 +36849,7 @@ package android.telephony {
     field public static final java.lang.String KEY_ALLOW_EMERGENCY_NUMBERS_IN_CALL_LOG_BOOL = "allow_emergency_numbers_in_call_log_bool";
     field public static final java.lang.String KEY_ALLOW_EMERGENCY_VIDEO_CALLS_BOOL = "allow_emergency_video_calls_bool";
     field public static final java.lang.String KEY_ALLOW_LOCAL_DTMF_TONES_BOOL = "allow_local_dtmf_tones_bool";
+    field public static final java.lang.String KEY_ALLOW_MERGE_WIFI_CALLS_WHEN_VOWIFI_OFF_BOOL = "allow_merge_wifi_calls_when_vowifi_off_bool";
     field public static final java.lang.String KEY_ALLOW_NON_EMERGENCY_CALLS_IN_ECM_BOOL = "allow_non_emergency_calls_in_ecm_bool";
     field public static final java.lang.String KEY_ALWAYS_SHOW_EMERGENCY_ALERT_ONOFF_BOOL = "always_show_emergency_alert_onoff_bool";
     field public static final java.lang.String KEY_APN_EXPAND_BOOL = "apn_expand_bool";
diff --git a/telecomm/java/android/telecom/Connection.java b/telecomm/java/android/telecom/Connection.java
index 39302081b79ad..2a0a9a640c6d7 100644
--- a/telecomm/java/android/telecom/Connection.java
+++ b/telecomm/java/android/telecom/Connection.java
@@ -586,6 +586,8 @@ public abstract class Connection extends Conferenceable {
         public void onExtrasChanged(Connection c, Bundle extras) {}
         public void onExtrasRemoved(Connection c, List<String> keys) {}
         public void onConnectionEvent(Connection c, String event, Bundle extras) {}
+        /** @hide */
+        public void onConferenceSupportedChanged(Connection c, boolean isConferenceSupported) {}
     }
 
     /**
@@ -2354,6 +2356,19 @@ public abstract class Connection extends Conferenceable {
         }
     }
 
+    /**
+     * Notifies listeners when a change has occurred to the Connection which impacts its ability to
+     * be a part of a conference call.
+     * @param isConferenceSupported {@code true} if the connection supports being part of a
+     *      conference call, {@code false} otherwise.
+     * @hide
+     */
+    protected void notifyConferenceSupportedChanged(boolean isConferenceSupported) {
+        for (Listener l : mListeners) {
+            l.onConferenceSupportedChanged(this, isConferenceSupported);
+        }
+    }
+
     /**
      * Sends an event associated with this {@code Connection}, with associated event extras.
      *
diff --git a/telephony/java/android/telephony/CarrierConfigManager.java b/telephony/java/android/telephony/CarrierConfigManager.java
index 2458cc8c85ae6..8399bb669da00 100644
--- a/telephony/java/android/telephony/CarrierConfigManager.java
+++ b/telephony/java/android/telephony/CarrierConfigManager.java
@@ -808,6 +808,16 @@ public class CarrierConfigManager {
     public static final String KEY_DROP_VIDEO_CALL_WHEN_ANSWERING_AUDIO_CALL_BOOL =
             "drop_video_call_when_answering_audio_call_bool";
 
+    /**
+     * Flag indicating whether the carrier supports merging wifi calls when VoWIFI is disabled.
+     * This can happen in the case of a carrier which allows offloading video calls to WIFI
+     * separately of whether voice over wifi is enabled.  In such a scenario when two video calls
+     * are downgraded to voice, they remain over wifi.  However, if VoWIFI is disabled, these calls
+     * cannot be merged.
+     */
+    public static final String KEY_ALLOW_MERGE_WIFI_CALLS_WHEN_VOWIFI_OFF_BOOL =
+            "allow_merge_wifi_calls_when_vowifi_off_bool";
+
     /** The default value for every variable. */
     private final static PersistableBundle sDefaults;
 
@@ -959,8 +969,9 @@ public class CarrierConfigManager {
         // Order is important - lowest precidence first
         sDefaults.putStringArray(KEY_RATCHET_RAT_FAMILIES,
                 new String[]{"1,2","7,8,12","3,11,9,10,15","14,19"});
-        sDefaults.putBoolean(KEY_TREAT_DOWNGRADED_VIDEO_CALLS_AS_VIDEO_CALLS_BOOL, true);
-        sDefaults.putBoolean(KEY_DROP_VIDEO_CALL_WHEN_ANSWERING_AUDIO_CALL_BOOL, true);
+        sDefaults.putBoolean(KEY_TREAT_DOWNGRADED_VIDEO_CALLS_AS_VIDEO_CALLS_BOOL, false);
+        sDefaults.putBoolean(KEY_DROP_VIDEO_CALL_WHEN_ANSWERING_AUDIO_CALL_BOOL, false);
+        sDefaults.putBoolean(KEY_ALLOW_MERGE_WIFI_CALLS_WHEN_VOWIFI_OFF_BOOL, true);
     }
 
     /**