We've been running Enterprise (now 'Quantum') with our data on Server 2012 since March of 2013 when our older SBS 2003 server went away. We have had no problems with the Connection Manager.

After saying goodbye to Crystal Reports, we've been keeping up with the latest releases for the past 12 months, so if any incompatible (with 2014.3) Microsoft service packs came out in the mean time we wouldn't have noticed.

Server 2012 was released in September of 2012, so probably anything from 2013.1 onward will run OK.