1 files changed, 7 insertions, 0 deletions
diff --git a/synapse/rest/client/sync.py b/synapse/rest/client/sync.py
index c2989765ce..8a16459105 100644
--- a/synapse/rest/client/sync.py
+++ b/synapse/rest/client/sync.py
@@ -100,6 +100,7 @@ class SyncRestServlet(RestServlet):
         self._server_notices_sender = hs.get_server_notices_sender()
         self._event_serializer = hs.get_event_client_serializer()
         self._msc2654_enabled = hs.config.experimental.msc2654_enabled
+        self._msc3773_enabled = hs.config.experimental.msc3773_enabled
 
     async def on_GET(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
         # This will always be set by the time Twisted calls us.
@@ -509,6 +510,12 @@ class SyncRestServlet(RestServlet):
             ephemeral_events = room.ephemeral
             result["ephemeral"] = {"events": ephemeral_events}
             result["unread_notifications"] = room.unread_notifications
+            if room.unread_thread_notifications:
+                result["unread_thread_notifications"] = room.unread_thread_notifications
+                if self._msc3773_enabled:
+                    result[
+                        "org.matrix.msc3773.unread_thread_notifications"
+                    ] = room.unread_thread_notifications
             result["summary"] = room.summary
             if self._msc2654_enabled:
                 result["org.matrix.msc2654.unread_count"] = room.unread_count