The Lync Server 2013 Mediation Server supports the following operating systems:
• Windows Server 2008 R2, Standard Edition with Service Pack 1
• Windows Server 2008 R2, Enterprise Edition with Service Pack 1
• Windows Server 2008 R2, Datacenter Edition with Service Pack 1
• Windows Server 2012, Standard Edition
• Windows Server 2012, Datacenter Edition
The Windows Server Core, Web, and High-Performance Computing Editions for any operating system version are not supported for deployment.