OCS 2007 R2 Server:
Office Communications Server 2007 R2 – KB 968802 – Download
Office Communications Server 2007 R2 Back-end database update – KB 2032834 – Download
OCS 2007 R2 Client:
Office Communicator 2007 R2 – KB 2028888 – Download
Office Communicator Phone Edition 2007 R2 – KB 2267962 – Download
Group Chat:
Office Communications Server 2007 R2, Group Chat Server – KB 2032881 – Download
Office Communications Server 2007 R2, Group Chat Client – KB 2032922 – Download
Office Communications Server 2007 R2, Group Chat Admin Tool – KB 2032949 – Download
