diff --git a/synapse/handlers/event_auth.py b/synapse/handlers/event_auth.py
index 7bbb833f303c..ed4149bd589c 100644
--- a/synapse/handlers/event_auth.py
+++ b/synapse/handlers/event_auth.py
@@ -48,7 +48,6 @@ def __init__(self, hs: "HomeServer"):
 
     async def check_auth_rules_from_context(
         self,
-        room_version_obj: RoomVersion,
         event: EventBase,
         context: EventContext,
     ) -> None:
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index b59641776932..6310f0ef27c8 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -799,9 +799,7 @@ async def on_make_join_request(
 
         # The remote hasn't signed it yet, obviously. We'll do the full checks
         # when we get the event back in `on_send_join_request`
-        await self._event_auth_handler.check_auth_rules_from_context(
-            room_version, event, context
-        )
+        await self._event_auth_handler.check_auth_rules_from_context(event, context)
         return event
 
     async def on_invite_request(
@@ -972,9 +970,7 @@ async def on_make_leave_request(
         try:
             # The remote hasn't signed it yet, obviously. We'll do the full checks
             # when we get the event back in `on_send_leave_request`
-            await self._event_auth_handler.check_auth_rules_from_context(
-                room_version_obj, event, context
-            )
+            await self._event_auth_handler.check_auth_rules_from_context(event, context)
         except AuthError as e:
             logger.warning("Failed to create new leave %r because %s", event, e)
             raise e
@@ -1033,9 +1029,7 @@ async def on_make_knock_request(
         try:
             # The remote hasn't signed it yet, obviously. We'll do the full checks
             # when we get the event back in `on_send_knock_request`
-            await self._event_auth_handler.check_auth_rules_from_context(
-                room_version_obj, event, context
-            )
+            await self._event_auth_handler.check_auth_rules_from_context(event, context)
         except AuthError as e:
             logger.warning("Failed to create new knock %r because %s", event, e)
             raise e
@@ -1208,7 +1202,7 @@ async def exchange_third_party_invite(
             try:
                 validate_event_for_room_version(event)
                 await self._event_auth_handler.check_auth_rules_from_context(
-                    room_version_obj, event, context
+                    event, context
                 )
             except AuthError as e:
                 logger.warning("Denying new third party invite %r because %s", event, e)
@@ -1259,9 +1253,7 @@ async def on_exchange_third_party_invite_request(
 
         try:
             validate_event_for_room_version(event)
-            await self._event_auth_handler.check_auth_rules_from_context(
-                room_version_obj, event, context
-            )
+            await self._event_auth_handler.check_auth_rules_from_context(event, context)
         except AuthError as e:
             logger.warning("Denying third party invite %r because %s", event, e)
             raise e
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index b078e2424f72..c8bbcfd8c274 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -42,7 +42,7 @@
     SynapseError,
     UnsupportedRoomVersionError,
 )
-from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersions
+from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
 from synapse.api.urls import ConsentURIBuilder
 from synapse.event_auth import validate_event_for_room_version
 from synapse.events import EventBase, relation_from_event
@@ -1273,23 +1273,6 @@ async def handle_new_client_event(
                 )
                 return prev_event
 
-        if event.is_state() and (event.type, event.state_key) == (
-            EventTypes.Create,
-            "",
-        ):
-            room_version_id = event.content.get(
-                "room_version", RoomVersions.V1.identifier
-            )
-            maybe_room_version_obj = KNOWN_ROOM_VERSIONS.get(room_version_id)
-            if not maybe_room_version_obj:
-                raise UnsupportedRoomVersionError(
-                    "Attempt to create a room with unsupported room version %s"
-                    % (room_version_id,)
-                )
-            room_version_obj = maybe_room_version_obj
-        else:
-            room_version_obj = await self.store.get_room_version(event.room_id)
-
         if event.internal_metadata.is_out_of_band_membership():
             # the only sort of out-of-band-membership events we expect to see here are
             # invite rejections and rescinded knocks that we have generated ourselves.
@@ -1299,7 +1282,7 @@ async def handle_new_client_event(
             try:
                 validate_event_for_room_version(event)
                 await self._event_auth_handler.check_auth_rules_from_context(
-                    room_version_obj, event, context
+                    event, context
                 )
             except AuthError as err:
                 logger.warning("Denying new event %r because %s", event, err)
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 44d9784077f6..d8918ee1aa26 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -226,10 +226,9 @@ async def upgrade_room(
                 },
             },
         )
-        old_room_version = await self.store.get_room_version(old_room_id)
         validate_event_for_room_version(tombstone_event)
         await self._event_auth_handler.check_auth_rules_from_context(
-            old_room_version, tombstone_event, tombstone_context
+            tombstone_event, tombstone_context
         )
 
         # Upgrade the room