Migration of all Lync Server topologies and server roles is supported. You can migrate from one topology to a different topology, including from Standard Edition server to Enterprise Edition server.

Lync Server 2013 supports only the following migration method:

• Side-by-side migration. In side-by-side migration, Lync Server 2013 is deployed alongside an existing Microsoft Lync Server 2010 or Office Communications Server 2007 R2 deployment, and then you transfer operations to the new servers and move users to Lync Server 2013. This method requires additional server platforms, including hardware and software, during migration, and system names and pool names are different in the new configuration. If it becomes necessary to roll back to the previous version, you can shift operations back to the previous servers.

Migration across Active Directory Domain Services forests is not supported.

The recommended migration path is a phased approach. For details about migrating from a previous release, including the appropriate phasing of component deployment, see the following topics in the Migration documentation:

• Migration from Lync Server 2010 to Lync Server 2013

• Migration from Office Communications Server 2007 R2 to Lync Server 2013

• Migration from Lync Server 2010, Group Chat or Office Communications Server 2007 R2 Group Chat to Lync Server 2013, Persistent Chat Server

Lync Server 2013 can coexist with components of either a Lync Server 2010 deployment or an Office Communications Server 2007 R2 deployment. Concurrent deployment of Lync Server 2013 with both Lync Server 2010 and Office Communications Server 2007 R2 (concurrent deployment of all three versions) is not supported.

During a phased migration in which a previous Lync Server 2010 or Office Communications Server 2007 R2 deployment coexists temporarily with the new Lync Server 2013 deployment, support for mixed version routing is limited. For details, see the Migration documentation.

You must use separate and distinct computers running Microsoft SQL Server 2008 R2 or Microsoft SQL Server 2012 for your Lync Server 2013 database instances. You cannot use the same instance of SQL Server for a Lync Server 2013 Front End pool that you use for a Lync Server 2010 or Office Communications Server 2007 R2 Front End pool. If you define and configure Lync Server 2013 in Topology Builder for a deployment that already has Lync Server 2010 or Office Communications Server 2007 R2 deployed, Topology Builder will not allow you to define an instance of a Lync Server 2013 that is already in use in the topology.

Topology Builder will display the following message to inform you of this issue: "The SQL server [FQDN of the server] already contains a SQL instance hosting role 'User Store'."

Note:

If you intend to deploy server roles that are new to your Lync Server 2013 deployment, you should first upgrade your existing deployment as described in the Migration documentation and the Deployment documentation, and then deploy the new server roles as described in the Planning documentation and Deployment documentation. If you are migrating a previous version of Group Chat, migrate it last, after completing the process for migrating all other components from Lync Server 2010 or Office Communications Server 2007 R2.

For specific coexistence requirements and other details about coexistence and migration of Lync Server 2010 or Office Communications Server 2007 R2 and Lync Server 2013 components, see Migration from Lync Server 2010 to Lync Server 2013 and Migration from Office Communications Server 2007 R2 to Lync Server 2013 in the Migration documentation. For details about mixed version support for clients, see Supported clients from previous deployments.