Here are the big things that have been fixed:
- Flight mode can now be enabled.
- You can now disable data connections.
- fixed the bug in which your phone’s MMS settings were lost after upgrading from Build 9941.
- fixed the issue in which you couldn’t download keyboards for additional languages.
- fixed the issue where the viewfinder in the Camera app gets composed incorrectly on some devices like the Lumia 1020
For Lumia 520 users:
Microsoft released an update to the Windows Phone Reset Tool that should get those impacted by the issue up and running. More information is available here. With this issue resolved problems with Lumia 520.