v2.9 Mobile changelog (#6661)

* Update mobile-app-changelog.md

* Update mobile-app-changelog.md

* Update mobile-app-changelog.md

* Add known issue

* Apply suggestions from code review

Co-authored-by: Carrie Warner (Mattermost) <[email protected]>

* Update mobile-app-changelog.md

* Update mobile-app-changelog.md

* Update mobile-app-changelog.md

* Update mobile-app-changelog.md

* Update mobile-app-changelog.md

* Update mobile-app-changelog.md

* Update mobile-app-changelog.md

* Update mobile-app-changelog.md

* Update mobile-app-changelog.md

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Co-authored-by: Carrie Warner (Mattermost) <[email protected]>

source/deploy/mobile-app-changelog.md

@@ -2,12 +2,39 @@
 
 Latest Mattermost Mobile Apps releases:
 
-- [2.8.2 Release](#release)
-- [2.8.1 Release](#id2)
-- [2.8.0 Release](#id5)
-- [2.7.0 Release](#id9)
-- [2.6.0 Release](#id14)
-- [2.5.1 Release](#id19)
+- [2.9.0 Release](#release)
+- [2.8.2 Release](#id1)
+- [2.8.1 Release](#id4)
+- [2.8.0 Release](#id9)
+- [2.7.0 Release](#id14)
+- [2.6.0 Release](#id19)
+
+## 2.9.0 Release
+- Release Date: October 16, 2023
+- Server Versions Supported: Server v7.8.0+ is required. Self-Signed SSL Certificates are not supported unless the user installs the CA certificate on their device.
+
+### Compatibility
+ - **Upgrade to server version v7.8.0 or later is required.** Support for server [Extended Support Release](https://docs.mattermost.com/upgrade/extended-support-release.html) (ESR) v7.1.0 has ended and upgrading to server ESR v7.8.0 or later is required. As we innovate and offer newer versions of our mobile apps, we maintain backwards compatibility only with supported server versions. Users who upgrade to the newest mobile apps while being connected to an unsupported server version can be exposed to compatibility issues, which can cause crashes or severe bugs that break core functionality of the app.
+ - Android operating system 7+ [is required by Google](https://android-developers.googleblog.com/2017/12/improving-app-security-and-performance.html).	
+ - iPhone 5s devices and later with iOS 12.4+ is required.
+
+### Improvements
+ - Added an alert showing the user that the server is using an invalid or untrusted SSL certificate.
+ - Calls: added wired headset support as an option in the Android build. iOS supports wired headset as the non-speakerphone output.
+ - Added changes for v9.1+ servers that send notifications for every message within group messages.
+
+### Bug Fixes
+ - Fixed an issue on Android where pressing the back button on certain settings did not always save the changes.
+ - Fixed a display error on the Multi-factor Authentication (MFA) screen.
+ - Fixed an issue where the **Following** button in the Thread view wrapped incorrectly.
+
+### Open Source Components
+ - Removed ``@rudderstack/rudder-sdk-react-native`` from https://github.com/mattermost/mattermost-mobile/.
+
+### Known Issues
+ - "Removed from channel" message is shown when a Direct Message channel is converted to a private channel [MM-54525](https://mattermost.atlassian.net/browse/MM-54525).
+ - Users are unable to adjust the font size via the OS font size setting.
+ - Some Google Pixel phones on Android 12+ might not continue past the login screen. This is a known issue with the OS, and the current workaround is to restart the device.
 
 ## 2.8.2 Release
 - Release Date: Oct 10, 2023