On 22.02.2012 Office Communications Server will be upgraded to a newer version. It’s a major upgrade and it is compatible only with Office Communicator Client version “3.5.6907.233” or higher.
If you use Office Communicator then verify that you have the proper version i. e. “3.5.6907.233” (or higher). This version of Office Communicator was already installed by CMF on all centrally managed Windows machines.
If you use an obsolete version of Office Communicator then you can install the compatible software from: \\cern.ch\dfs\Applications\Microsoft\OfficeCommunicator2007\Office Communicator 3.5.6907.233\Communicator_KB2549042.msp