Microsoft published a new Updates Resource Center for Office Communications Server 2007 R2 and Clients on OCS TechCenter. In addition, Sustained Engineering and support teams have created a Cumulative Server Update Installer tool to help simplify application of updates. The Cumulative Server Update Installer applies all updates for appropriate server role in one click! Each link text on Updates Resource Center page contains release date for update so that you can easily recognize whether you’ve most recent updates. Each link leads to a Knowledge Base article that lists contents of updater, describes issues fixed, and provides other important installation information–in addition to pointing to actual downloadable file.
More info: Updates Resource Center