The following items are coexistence concerns that will affect how you plan your Office Communications Server 2007 R2 migration and deployment:

As noted previously, Office Communications Server 2007 R2, Monitoring Server, will not collect data from traffic that is hosted on Office Communications Server 2007; however, for Enterprise Voice coexistence, Office Communications Server 2007, Mediation Server, may need to be associated with the 2007 R2 release of the Monitoring Server. To do so, you must download and run the script Associate.vbs on a machine that has the Office Communications Server 2007 R2 snap-in. The script and usage instructions are available for download from “Associate Office Communication Server 2007 or Office Communication Server 2007 R2 Mediation Server with Office Communication Server 2007 R2 Pool” at l http://go.microsoft.com/fwlink/?LinkId=145133 .