diff --git a/src/com/android/services/telephony/TelephonyConnection.java b/src/com/android/services/telephony/TelephonyConnection.java
index d6fb3ad..2b0f49f 100644
--- a/src/com/android/services/telephony/TelephonyConnection.java
+++ b/src/com/android/services/telephony/TelephonyConnection.java
@@ -538,6 +538,7 @@
         @Override
         public void onRttModifyResponseReceived(int status) {
             updateConnectionProperties();
+            refreshConferenceSupported();
             if (status == RttModifyStatus.SESSION_MODIFY_REQUEST_SUCCESS) {
                 sendRttInitiationSuccess();
             } else {
@@ -554,7 +555,12 @@
 
         @Override
         public void onRttInitiated() {
-            updateConnectionProperties();
+            if (mOriginalConnection != null) {
+                // if mOriginalConnection is null, the properties will get set when
+                // mOriginalConnection gets set.
+                updateConnectionProperties();
+                refreshConferenceSupported();
+            }
             sendRttInitiationSuccess();
         }
 
@@ -2117,6 +2123,9 @@
         if (mTreatAsEmergencyCall) {
             isConferenceSupported = false;
             Log.d(this, "refreshConferenceSupported = false; emergency call");
+        } else if (isRtt()) {
+            isConferenceSupported = false;
+            Log.d(this, "refreshConferenceSupported = false; rtt call");
         } else if (!isConferencingSupported || isIms && !isImsConferencingSupported) {
             isConferenceSupported = false;
             Log.d(this, "refreshConferenceSupported = false; carrier doesn't support conf.");