Programming Lync
From Logic Wiki
To download SDKs go to https://technet.microsoft.com/en-us/office/dn788954
Download Microsoft Lync 2013 SDK
Download Lync Server SDK
Before installation of server SDK make sure that Microsoft Visual C++ 2012 Redistributable (x64) - 11.0.50727 is installed. (Exact this version is needed)
you can download it from http://www.freewarefiles.com/downloads_counter.php?programid=78882