Merge 2fca4789ca into bb3daafe96

changelogs/client_server/newsfragments/2304.clarification

@@ -1 +0,0 @@
-Clarify the requiredness of `event_id` in `predecessor`.

content/client-server-api/modules/room_upgrades.md

@@ -43,8 +43,8 @@ They must be explicitly set during the `/upgrade` call.
 {{% /boxes/note %}}
 
 {{% boxes/note %}}
-{{% added-in v="1.16" %}} When upgrading to room version 12 or later, the `event_id` property inside
-`predecessor` MAY be omitted.
+{{% added-in v="1.16" %}} When upgrading to room version 12 or later, the `predecessor` field MAY NOT contain
+an `event_id`.
 {{% /boxes/note %}}
 
 3.  Replicates transferable state events to the new room. The exact