On July 12th, 2016 Microsoft Dynamics SL 2011 will be moving from mainstream support to extended support. Support will still be available for supported versions.
The supported versions are:
However, the end of mainstream support means there will be no more hot fixes. Hot fixes are created to address an issue with the product when it is not working as designed and a workaround is not available. With a product that has been available for five years, most of the major bugs have already been addressed. There has only been four hot fixes for Dynamics SL 2011 SP3.
Typically, the end of mainstream support will also mean the end of Year End Updates. However, Microsoft is making a one-time extension for the 2016 Year End Updates for the support versions mentioned above.
So, if you running SL 2011, what does this mean? Well, you are running SL 2011 without any service packs or just SP1, you should plan on applying at least SP2 as soon as possible, so you are on a supported version. If you are on a supported version, plans should be in the works to upgrade to SL 2015 (or the next version) and go live sometime in early 2017, if not earlier.