Microsoft has released updates for Exchange Server 2013, 2010, and 2007 as part of their quarterly release cadence. The 2007 and 2010 RUs are bug fixes to the product and not introducing new features (well techincally 2007 a few) while the Service Pack for 2013 adds a load of function and features. Like all past updates and future updates the download is huge as it is the entire bit-set rolled up into the distributable so don’t be alarmed to see a 1.53GB file coming down the pipe.
Information regarding the releases and new features may be found on the TechNet Exchange blogs and the links to the downloads may be found below. The TAP program these past few go-arounds have included the Exchange MVPs as well as external client which means the most critical set of eyes were looking at this 2013 release.
Exchange Server 2013 SP1
Exchange Server 2010 SP3 RU 5
Exchange Server 2007 SP3 RU 13