Draft changelog: Livestream API, chat moderators, XAA post_id qualifier

changelog.mdx

@@ -7,6 +7,38 @@ keywords: ["changelog", "API updates", "release notes", "what's new", "API chang
 
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+<Update label="Sep 16, 2026" description="Livestream API">
+  ### Livestream API is now available (Enterprise)
+
+  The [Livestream API](/livestream-api/introduction) is now available under the Enterprise plan. It provides a complete set of endpoints for managing live video broadcasts on X:
+
+  - Persistent RTMP/RTMPS [stream sources](/livestream-api/sources/overview) you create once per encoder or region and reuse across broadcasts
+  - The full [broadcast lifecycle](/livestream-api/broadcasts/overview) (`NOT_STARTED` → `RUNNING` → `ENDED`), including publish and end
+  - One-time and recurring [scheduled broadcasts](/livestream-api/scheduled-broadcasts/overview) that publish automatically or wait for an explicit go-live
+  - [Reading live chat](/livestream-api/chat/accessing-live-chat) via the X Activity API and [sending chat messages](/livestream-api/chat/send-chat-message) into a broadcast
+  - Moderating live chat: [delete messages](/livestream-api/chat/delete-chat-message), [mute](/livestream-api/chat/mute-chat-user) and [unmute](/livestream-api/chat/unmute-chat-user) chat users
+
+  See the [typical workflow](/livestream-api/typical-workflow) to go from stream source to live broadcast. If you are interested in access, fill out the [Enterprise interest form](/forms/enterprise-api-interest).
+</Update>
+
+<Update label="Sep 16, 2026" description="Livestream API">
+  ### Broadcast chat moderators
+
+  You can now delegate live chat moderation to other users. Moderators are scoped to the authenticated broadcaster (not to an individual broadcast) and can moderate chat across every broadcast that user hosts. Each broadcaster can have up to 20 moderators.
+
+  - [`POST /2/broadcasts/chat/moderators`](/livestream-api/chat/add-moderator) adds a moderator
+  - [`GET /2/broadcasts/chat/moderators`](/livestream-api/chat/list-moderators) lists current moderators
+  - [`DELETE /2/broadcasts/chat/moderators/:id`](/livestream-api/chat/remove-moderator) removes a moderator
+
+  Moderators can call [delete chat message](/livestream-api/chat/delete-chat-message), [mute chat user](/livestream-api/chat/mute-chat-user), and [unmute chat user](/livestream-api/chat/unmute-chat-user) on the broadcaster's behalf.
+</Update>
+
+<Update label="Sep 16, 2026" description="X API v2">
+  ### `post_id` qualifier for `like.create` on X Activity API
+
+  The [X Activity API](/x-api/activity/introduction) now accepts a `post_id` qualifier on `like.create` subscriptions. Set `filter.qualifiers.post_id` to a Post ID to receive `like.create` events only for likes on that specific Post, instead of for every like by the subscribed user.
+</Update>
+
 <Update label="Sep 15, 2026" description="X Ads API">
   ### Lead Generation API