1 files changed, 1 insertions, 1 deletions
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 08244b690d..343e3c6b7b 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -644,7 +644,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
             if block_invite:
                 raise SynapseError(403, "Invites have been disabled on this server")
 
-        if prev_event_ids:
+        if prev_event_ids is not None:
             return await self._local_membership_update(
                 requester=requester,
                 target=target,