Autodesk® Maya® provides a rich and powerful API that can be used to automate repetitive tasks, and to extend the core functionality of Maya. This functionality includes customization of 3D modeling, animation, visual effects, rendering, and many other areas. C++, Python, and .NET are supported. The Software Development Kit (SDK) provides extensive functionality and provides code samples and documentation to help get you started developing with the Maya API. The Extension 2 libraries are not binary compatible with Maya 2016 and SP libraries and vice et versa.
C++ plug-ins that were compiled against Maya 2016 or Maya 2016 Extension 1, including Maya 2016 service pack releases, must be re-compiled against Maya 2016 Extension 2 in order to be recognized by this version of Maya.
In addition, plug-ins compiled against Maya 2016 Extension 2 will either not load or exhibit unpredictable behavior if loaded in Maya 2016, Maya 2016 Extension 1, or any Maya 2016 service pack release.
See the what’s New in API in Maya 2016 Extension 2 documentation http://www.autodesk.com/maya-help-2016-enu/?contextId=WHATS_NEW_API_2016EXT2