On November 1st, Microsoft released MDOP 2012. Besides the general availability of App-V 5 and an update of DaRT (v8), Microsoft has introduced UE-V.
More info can be found here:
App-V 4.6 SP2 is also a part of the MDOP 2012 download, which you will need to support the App-V 4.6 and App-V 5 “co-existence mode”. In addition App-V 4.6 SP2 also supports Windows 8 and Windows Server 2012, so you are not forced to update to App-V 5 just to support Windows 8 for instance.