http://blogs.technet.com/b/omers/archive/2012/02/17/released-update-rollup-1-for-exchange-2010-service-pack-2.aspxThe Exchange CXP team released Update Rollup 1 for Exchange Server 2010 SP2 to the Download Center. This update contains a number of customer-reported and internally found issues since the release of SP2. See KB 2645995 : Description of Update Rollupen-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)