If your current deployment includes the 2007 release of Microsoft Office Communicator Web Access, you will need to deploy the 2007 R2 release.
Users of Communicator Web Access can use only the release that corresponds to the version of Office Communications Server where they are homed. As long as you have users who are homed on Office Communications Server 2007, you will need to retain the 2007 release of Communicator Web Access.
As part of deploying the 2007 R2 release of Communicator Web Access, you will need to modify existing DNS records that are associated with Communicator Web Access so that they direct all users to the 2007 R2 release of Communicator Web Access. For details, see in the Deploying Communicator Web Access (2007 R2 Release) documentation. You will then configure the new Communicator Web Access server so that users who are homed on Office Communications Server 2007 are redirected to the 2007 release of Communicator Web Access.
Alternatively, you can create separate URLs and DNS records for internal and external users of each release of Communicator Web Access, but this approach will require additional communication with your users as you move them to the 2007 R2 release.
For details about DNS requirements, see Configuring Communicator Web Access DNS Recordsin the Office Communications Server 2007 R2 documentation.
For details about installing Communicator Web Access, see the documentation.
If you are maintaining separate DNS records for users who are still homed on Office Communications Server 2007, you will need to configure the reverse proxy to provide paths for users of both releases of Communicator Web Access.
For details on user experience during this phase, see User Experience During Phase 6.