send expiration timer update only to added members in closed group

js/models/conversations.js

@@ -1903,6 +1903,7 @@
 
       await this.sendClosedGroupMessageWithSync(groupUpdateMessage, recipients);
 
+      if (groupUpdate.joined && groupUpdate.joined.length) {
         const expireUpdate = {
           timestamp: Date.now(),
           expireTimer: this.get('expireTimer'),
@@ -1912,7 +1913,16 @@
         const expirationTimerMessage = new libsession.Messages.Outgoing.ExpirationTimerUpdateMessage(
           expireUpdate
         );
-      await libsession.getMessageQueue().sendToGroup(expirationTimerMessage);
+        await Promise.all(
+          groupUpdate.joined.map(async join => {
+            const device = new libsession.Types.PubKey(join);
+            await libsession
+              .getMessageQueue()
+              .sendUsingMultiDevice(device, expirationTimerMessage)
+              .catch(log.error);
+          })
+        );
+      }
     },
 
     async sendGroupInfo(recipient) {