"This release of Mumble concludes the 1.1.X series. It stays backwards compatible and adds further functionality to the client and the server. The client received a lot of new PA plugins, the ability to play sound files (.spx format) instead of TTS, balloon notifications and a lot of other bugfixes and enhancements. The servers resource usage was optimized and the ICE RPC Interface was extended and offers some very powerfull new possibilities."
- from mumble.sourceforge.net/Main_Page
well, its backwards compatible and we dont have any problems so there is no need to upgrade. i was bored