Hosted Messaging and Collaboration version 4.5 introduces a new service component, Microsoft Office Communications Server 2007 to the solution. Hosted Office Communications Server 2007 can be deployed to support instant messaging (IM), group IM, PC-based audio and video, Web conferencing, and online presence. These features extend the service offerings for Hosted Messaging and Collaboration version 4.5, by providing a comprehensive set of communications capabilities for customers to use and for service providers to offer.

Microsoft Provisioning System (MPS) automates the provisioning of Office Communications Server 2007 resources, users, and organizations. In addition, the protocols included with Office Communications Server enable it to become a platform for applications such as PBX and PSTN telephony systems.