diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index afc4582979..4e38b95eaf 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -445,6 +445,7 @@ class PresenceHandler(object):
         Returns:
             set(str): A set of user_id strings.
         """
+        return set()
         syncing_user_ids = {
             user_id for user_id, count in self.user_to_num_current_syncs.items()
             if count