Today there are new updates for Exchange Server 2007, Exchange Server 2010 and Exchange Server 2013:
Cumulative Update 7 for Exchange Server 2013 (KB2986485)
UM language packs for Exchange Server 2013 CU7
Update rollup 8 for Exchange Server 2010, Service Pack 3 (KB2986475)
Update rollup 15 for Exchange Server 2007 Service Pack 3 (KB2996150)
So far there is no overview of which specific problems have been fixed. However, the AD schema will be raised for Exchange 2013.