Supports multi-dimenstional grouping

CHANGELOG.md

@@ -32,6 +32,7 @@ Notes: web developers are advised to use [`~` (tilde range)](https://github.com/
    - Please refer to PR [#5330](https://github.com/microsoft/BotFramework-WebChat/pull/5330) for details
 - HTML sanitizer is moved from `renderMarkdown` to HTML content transformer middleware, please refer to PR [#5338](https://github.com/microsoft/BotFramework-WebChat/pull/5338)
    - If you customized `renderMarkdown` with a custom HTML sanitizer, please move the HTML sanitizer to the new HTML content transformer middleware
+- `useGroupActivities` hook is being deprecated in favor of the `useGroupActivitiesByName` hook. The hook will be removed on or after 2027-05-04
 
 ### Added
 
@@ -86,6 +87,10 @@ Notes: web developers are advised to use [`~` (tilde range)](https://github.com/
 - Added sliding dots typing indicator in Fluent theme, in PR [#5447](https://github.com/microsoft/BotFramework-WebChat/pull/5447) and PR [#5448](https://github.com/microsoft/BotFramework-WebChat/pull/5448), by [@compulim](https://github.com/compulim)
 - (Experimental) Add an ability to pass `completion` prop into Fluent send box and expose the component, in PR [#5466](https://github.com/microsoft/BotFramework-WebChat/pull/5466), by [@OEvgeny](https://github.com/OEvgeny)
 - Added feedback form for like/dislike button when `feedbackActionsPlacement` is `"activity-actions"`, in PR [#5460](https://github.com/microsoft/BotFramework-WebChat/pull/5460), PR [#5469](https://github.com/microsoft/BotFramework-WebChat/pull/5469), and PR [5470](https://github.com/microsoft/BotFramework-WebChat/pull/5470) by [@lexi-taylor](https://github.com/lexi-taylor) and [@OEvgeny](https://github.com/OEvgeny)
+- Added multi-dimensional grouping, `styleOptions.groupActivitiesBy`, and `useGroupActivitiesByName` hook, in PR [#5471](https://github.com/microsoft/BotFramework-WebChat/pull/5471), by [@compulim](https://github.com/compulim)
+   - Existing behavior will be kept and activities will be grouped by `sender` followed by `status`
+   - `useGroupActivitiesByName` is favored over the existing `useGroupActivities` hook for performance reason
+   - Middleware which support the new grouping name init argument should only compute the grouping if they match the grouping name, or the grouping name is not specified, otherwise, should do nothing and call the downstream middleware
 
 ### Changed