Enterprise Voice users who are homed on an Office Communications Server 2007 pool will experience no change.
Enterprise Voice users who are homed on an Office Communications Server 2007 R2 pool and whose call route is assigned an Office Communications Server 2007 Mediation Server will experience no change.
Enterprise Voice users who are homed on an Office Communications Server 2007 R2 pool and whose call route is assigned an Office Communications Server 2007 R2 Mediation Server will experience no change until you deploy Office Communicator 2007 R2.