diff --git a/synapse/handlers/profile.py b/synapse/handlers/profile.py
index 834b37f5f..7853bf509 100644
--- a/synapse/handlers/profile.py
+++ b/synapse/handlers/profile.py
@@ -202,7 +202,6 @@ class ProfileHandler(BaseHandler):
 
             content = {
                 "membership": j.content["membership"],
-                "prev": j.content["membership"],
             }
 
             yield self.distributor.fire(
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index d09743ed1..7d9458e1d 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -364,9 +364,6 @@ class RoomMemberHandler(BaseHandler):
             target_user_id, event.room_id
         )
 
-        if prev_state:
-            event.content["prev"] = prev_state.membership
-
         room_id = event.room_id
 
         # If we're trying to join a room then we have to do this differently
diff --git a/tests/rest/test_rooms.py b/tests/rest/test_rooms.py
index ad3631d51..ff7c9f053 100644
--- a/tests/rest/test_rooms.py
+++ b/tests/rest/test_rooms.py
@@ -840,7 +840,6 @@ class RoomMemberStateTestCase(RestTestCase):
 
         expected_response = {
             "membership": Membership.JOIN,
-            "prev": Membership.JOIN,
         }
         self.assertEquals(expected_response, response)