In the story so far, Johan has described how to check that the migration from your OCS to Lync is supported and how to determine the requirements for the new installation This was followed by a walk-through of the preparation the Active Directory and installation of the first Lync Front End Server with a Mediation Server co-located. Now Johan tackles the merging the OCS configuration, and connection to the outsode world, followed by testing, performing and then validating the migration.