Service Pack 1 for Exchange Server 2013 has just been released. The Service Pack 1 now brings the long-awaited support for Windows Server 2012 R2 and the Edge Transport role is also available again.
The biggest news, however, is probably a new protocol for Outlook: MAPIoverHTTP.
The Service Pack 1 requires an AD schema update. The SP1 can be downloaded here:
Microsoft Exchange Server 2013 Service Pack 1 (SP1)
Here is a description of all the new features:
http://technet.microsoft.com/en-us/library/jj907309(v=exchg.150).aspx
I will report more details in the next few days.