Merge 2fca4789ca into f92c3579ac

changelogs/client_server/newsfragments/2299.feature

@@ -1 +0,0 @@
-Clients supporting the `ol` HTML element must also support the `start` attribute, as per [MSC4313](https://github.com/matrix-org/matrix-spec-proposals/pull/4313).

changelogs/room_versions/newsfragments/2303.clarification

@@ -1 +0,0 @@
-Remove the post-1.16 release note for room version 12.

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

@@ -84,10 +84,6 @@ Additionally, web clients should ensure that *all* `a` tags get a
 `rel="noopener"` to prevent the target page from referencing the
 client's tab/window.
 
-{{% added-in v="1.18" %}} Clients that support rendering numbered lists via the
-`ol` tag MUST also support the `start` attribute in order to prevent loss of
-meaning of a message due to the numbering of list items.
-
 Tags must not be nested more than 100 levels deep. Clients should only
 support the subset of tags they can render, falling back to other
 representations of the tags where possible. For example, a client may

content/rooms/_index.md

@@ -56,6 +56,19 @@ Clients should not ask room administrators to upgrade their rooms if the
 room is running a stable version. Servers SHOULD use **room version 12** as
 the default room version when creating new rooms.
 
+{{% boxes/note %}}
+
+{{% added-in v="1.16" %}}
+
+Room version 12 is introduced and made default in this specification release.
+Servers are encouraged to continue using room version 11 as the default room
+version for the early days and weeks following this specification release,
+and then gradually switch the default over when they deem appropriate.
+
+<!-- TODO(SCT): Remove this note box in Matrix 1.17 -->
+
+{{% /boxes/note %}}
+
 The available room versions are:
 
 -   [Version 1](/rooms/v1) - **Stable**. The initial room version.