fix(presence) Fix backwards compat with endpoints that don't send sourceInfo in presence.

modules/xmpp/ChatRoom.js

 import { $iq, $msg, $pres, Strophe } from 'strophe.js';
 
 import * as JitsiTranscriptionStatus from '../../JitsiTranscriptionStatus';
+import { MediaType } from '../../service/RTC/MediaType';
+import { VideoType } from '../../service/RTC/VideoType';
 import { XMPPEvents } from '../../service/xmpp/XMPPEvents';
 import GlobalOnErrorHandler from '../util/GlobalOnErrorHandler';
 import Listenable from '../util/Listenable';
         return this.role === 'moderator';
     }
 
+    /**
+     * Obtains the info about given media advertised (in legacy format) in the MUC presence of the participant
+     * identified by the given endpoint JID. This is for mantining interop with endpoints that do not support
+     * source-name signaling (Jigasi and very old mobile clients).
+     *
+     * @param {string} endpointId the endpoint ID mapped to the participant which corresponds to MUC nickname.
+     * @param {MediaType} mediaType the type of the media for which presence info will be obtained.
+     * @return {PeerMediaInfo} presenceInfo an object with media presence info or <tt>null</tt> either if there
+     * is no presence available or if the media type given is invalid.
+     */
+    getMediaPresenceInfo(endpointId, mediaType) {
+        // Will figure out current muted status by looking up owner's presence
+        const pres = this.lastPresences[`${this.roomjid}/${endpointId}`];
+
+        if (!pres) {
+            // No presence available
+            return null;
+        }
+        const data = {
+            muted: true, // muted by default
+            videoType: mediaType === MediaType.VIDEO ? VideoType.CAMERA : undefined // 'camera' by default
+        };
+        let mutedNode = null;
+
+        if (mediaType === MediaType.AUDIO) {
+            mutedNode = filterNodeFromPresenceJSON(pres, 'audiomuted');
+        } else if (mediaType === MediaType.VIDEO) {
+            mutedNode = filterNodeFromPresenceJSON(pres, 'videomuted');
+            const codecTypeNode = filterNodeFromPresenceJSON(pres, 'jitsi_participant_codecType');
+            const videoTypeNode = filterNodeFromPresenceJSON(pres, 'videoType');
+
+            if (videoTypeNode.length > 0) {
+                data.videoType = videoTypeNode[0].value;
+            }
+            if (codecTypeNode.length > 0) {
+                data.codecType = codecTypeNode[0].value;
+            }
+        } else {
+            logger.error(`Unsupported media type: ${mediaType}`);
+
+            return null;
+        }
+
+        if (mutedNode.length > 0) {
+            data.muted = mutedNode[0].value === 'true';
+        }
+
+        return data;
+    }
+
     /**
      *
      * @param peerJid