On August 26 Microsoft released Exchange 2013 CU6, the sixth Cumulative Update since the new servicing model of Exchange.
Unfortunately this Update in is facing issues. Some customers found two issues with Exchange 2013 CU6:
- Exchange Server 2013 databases unexpectedly fail over in a co-existence environment with Exchange Server 2007 – http://support.microsoft.com/kb/2997209
- Exchange Online mailboxes cannot be managed by using EAC after you deploy Exchange Server 2013 CU6 –http://support.microsoft.com/kb/2997355
Both issues were quickly identified by Microsoft and a fix is already available.