Lync Server 2010 Apr 2011 CU was released. Below is the detail information.

 Server

2514975  Description of the cumulative update for Lync Server 2010, Conferencing Server: April 2011

2500442 Description of the cumulative update for Lync Server 2010: April 2011

2500444 Description of the cumulative update for Lync Server 2010, Core Components: April 2011

2530592 Description of the cumulative update for Lync Server 2010, Web Conferencing Server: April 2011

2502810 Description of the cumulative update for Lync Server 2010, Mediation Server: April 2011

2500448 Description of the cumulative update for Lync Server 2010, Unified Communications Managed API 3.0 Runtime: April 2011

Client

2496325 Description of the cumulative update package for Lync 2010: April 2011

2529978 Description of the cumulative update for Lync 2010 Phone Edition for Aastra 6721ip and Aastra 6725ip: April 2011

2529977 Description of the cumulative update for Lync 2010 Phone Edition for Polycom CX500, Polycom CX600, and Polycom CX3000: April 2011

2529974 Description of the cumulative update for Microsoft Lync 2010 Phone Edition for Polycom CX700 and LG-Nortel IP Phone 8540: April 2011

 

Note: For the Update version information for each CU, please refer to the follow link:

http://blogs.technet.com/b/hot/archive/2012/09/24/update-version-information-for-lync-server-2010.aspx