Sorun : This version of Lync has been blocked by your system administrator. Please check for updates or contact your support team.

Çözüm :

Go to LYNC Control Panel...

Goto client - > Clients version configuration
The Global setting is set to "Enable Version control"

Goto Client Version Policy, edit the Global and see, what is allowed or blocked here...
And check the version of your client, if it fits to a block rule
And make sure, the LYNc client and Lync Server are up to date...