diff --git a/changelog.d/6823.misc b/changelog.d/6823.misc
new file mode 100644
index 0000000000..08aa80bcd9
--- /dev/null
+++ b/changelog.d/6823.misc
@@ -0,0 +1 @@
+Refactoring work in preparation for changing the event redaction algorithm.
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index 3a840e068b..110e42b9ed 100644
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -230,7 +230,7 @@ class FederationClient(FederationBase):
         self,
         destinations: Iterable[str],
         event_id: str,
-        room_version: str,
+        room_version: RoomVersion,
         outlier: bool = False,
         timeout: Optional[int] = None,
     ) -> Optional[EventBase]:
@@ -262,7 +262,7 @@ class FederationClient(FederationBase):
 
         pdu_attempts = self.pdu_destination_tried.setdefault(event_id, {})
 
-        format_ver = room_version_to_event_format(room_version)
+        format_ver = room_version.event_format
 
         signed_pdu = None
         for destination in destinations:
@@ -292,7 +292,9 @@ class FederationClient(FederationBase):
                     pdu = pdu_list[0]
 
                     # Check signatures are correct.
-                    signed_pdu = await self._check_sigs_and_hash(room_version, pdu)
+                    signed_pdu = await self._check_sigs_and_hash(
+                        room_version.identifier, pdu
+                    )
 
                     break
 
@@ -663,7 +665,7 @@ class FederationClient(FederationBase):
     async def send_invite(
         self, destination: str, room_id: str, event_id: str, pdu: EventBase,
     ) -> EventBase:
-        room_version = await self.store.get_room_version_id(room_id)
+        room_version = await self.store.get_room_version(room_id)
 
         content = await self._do_send_invite(destination, pdu, room_version)
 
@@ -671,20 +673,17 @@ class FederationClient(FederationBase):
 
         logger.debug("Got response to send_invite: %s", pdu_dict)
 
-        room_version = await self.store.get_room_version_id(room_id)
-        format_ver = room_version_to_event_format(room_version)
-
-        pdu = event_from_pdu_json(pdu_dict, format_ver)
+        pdu = event_from_pdu_json(pdu_dict, room_version.event_format)
 
         # Check signatures are correct.
-        pdu = await self._check_sigs_and_hash(room_version, pdu)
+        pdu = await self._check_sigs_and_hash(room_version.identifier, pdu)
 
         # FIXME: We should handle signature failures more gracefully.
 
         return pdu
 
     async def _do_send_invite(
-        self, destination: str, pdu: EventBase, room_version: str
+        self, destination: str, pdu: EventBase, room_version: RoomVersion
     ) -> JsonDict:
         """Actually sends the invite, first trying v2 API and falling back to
         v1 API if necessary.
@@ -701,7 +700,7 @@ class FederationClient(FederationBase):
                 event_id=pdu.event_id,
                 content={
                     "event": pdu.get_pdu_json(time_now),
-                    "room_version": room_version,
+                    "room_version": room_version.identifier,
                     "invite_room_state": pdu.unsigned.get("invite_room_state", []),
                 },
             )
@@ -719,8 +718,7 @@ class FederationClient(FederationBase):
                 # Otherwise, we assume that the remote server doesn't understand
                 # the v2 invite API. That's ok provided the room uses old-style event
                 # IDs.
-                v = KNOWN_ROOM_VERSIONS.get(room_version)
-                if v.event_format != EventFormatVersions.V1:
+                if room_version.event_format != EventFormatVersions.V1:
                     raise SynapseError(
                         400,
                         "User's homeserver does not support this room version",
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 8c6a142991..ef3cc264b7 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -1156,7 +1156,7 @@ class FederationHandler(BaseHandler):
         Logs a warning if we can't find the given event.
         """
 
-        room_version = await self.store.get_room_version_id(room_id)
+        room_version = await self.store.get_room_version(room_id)
 
         event_infos = []
 
@@ -1962,11 +1962,7 @@ class FederationHandler(BaseHandler):
 
         for e_id in missing_auth_events:
             m_ev = await self.federation_client.get_pdu(
-                [origin],
-                e_id,
-                room_version=room_version.identifier,
-                outlier=True,
-                timeout=10000,
+                [origin], e_id, room_version=room_version, outlier=True, timeout=10000,
             )
             if m_ev and m_ev.event_id == e_id:
                 event_map[e_id] = m_ev