1 files changed, 2 insertions, 1 deletions
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index a6dbff637f..447e3ce571 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -658,7 +658,8 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
             if block_invite:
                 raise SynapseError(403, "Invites have been disabled on this server")
 
-        if prev_event_ids:
+        # An empty prev_events list is allowed as long as the auth_event_ids are present
+        if prev_event_ids is not None:
             return await self._local_membership_update(
                 requester=requester,
                 target=target,