To ensure that you have the latest version of the Lync client, and the latest update, check out this frequently updated list of all client release versions for Microsoft Lync 2013.
Authors: Akshat Nigam, Microsoft Senior Support Engineer and Thomas Binder, Microsoft UC Voice Architect
Published: March 26, 2013
Updated: April 8, 2014
Product version: Lync 2013
One of the most common checks that we do when troubleshooting Lync client issues is determining whether you are running the latest version of the Lync client and if all patches are installed.
Read more at source: http://blogs.technet.com/b/nexthop/archive/2014/04/08/lync-2013-cumulative-updates-list.aspx