http://blogs.technet.com/b/omers/archive/2012/12/05/exchange-server-2013-reaches-general-availability.aspxBack in October , we announced that the Release to Manufacturing (RTM) build of Exchange Server 2013 was signed off. Since that time, we’ve been focusing our efforts on releasing the next version of Exchange through multiple distribution channels to ouren-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)