Just in case you missed this week’s kb, Lync Server 2010 can now be installed into an Active Directory where the forest and domain are at the Server 2012 functional level.
This brings Lync Server 2010 into alignment with Lync Server 2013 plus Exchange 2010 & 2013, all of which are OK on functional levels of Server 2003 Native and up. (Double-check the links below if you’re still living in the dark ages of 2003 Mixed).
kb 2869728 , 12 July 2013: Windows Server 2012 Active Directory Directory Services support for Lync Server 2010
Lync 2010: Active Directory Infrastructure Requirements
Lync 2013: Active Directory Infrastructure Requirements
Exchange 2010 System Requirements
Exchange 2013 System Requirements