Today Microsoft have released a new slew of updates for On Premise Exchange environments!
There have been various hotfixes and scripts released to fix a multitude of sins in Exchange 2013 CU6, and Microsoft have rolled these hotfixes and more into their latest CU7 release. This update does require a Schema Update, so please run setup /prepareschema first. See https://support.microsoft.com/kb/2986485 for more information. Additionally there are some UM Language Packs for Exchange 2013 CU7 available.
In other news, the Exchange 2010 CU8 update has been recalled at the time of writing and is not available for download. This is because deployment of said update can lead to Outlook being unable to connect to Exchange If you have already installed, it is recommended that you rollback the update.
Lastly is the Exchange 2007 SP3 UR15 for all those retro Exchange nerds still running Exchange 2007. See KB here for information http://support2.microsoft.com/?kbid=2996150.
Check out http://blogs.technet.com/b/exchange/archive/2014/12/09/exchange-releases-december-2014.aspx for the full rundown!