If you are still running Exchange 2010 you now have limited support options, without an extended support contract. Microsoft will still provide security updates to it until 1/14/2020 and may provide other updates for 2010 SP3, but no guarantees on those, and only those with an Extended Hotfix Support contract are entitled to them officially. “Mainstream” support ended on 1/13/2015, see Microsoft Support Lifecycle details on Exchange 2010 here. Pay support is still provided, but if you come across a bug/issue don’t expect a hotfix for it. The content in TechNet and other forums will still be available and is pretty solid after 5 years.
So if you’re organization is still on Exchange 2010 you need to be looking at migrating to Exchange 2013 or Office 365 ASAP!
From: http://support2.microsoft.com/gp/lifepolicy and see the Lifecycle support FAQ here.