Microsoft has issued the final beta on Exchange Server 2010 along with the final beta of its security companion, Forefront for Exchange Server 2010.

The newest Exchange Server, which is 64-bit only, is expected to ship before year-end. 

The 2010 version of Exchange is being touted as a hybrid - equally at home as the foundation for a hosted email service or a corporate messaging infrastructure. Microsoft already hosts more than 5 million users on Exchange 2010 as part of its [email protected] programme.

Michael Atalla, group product manager for Exchange, announced the release on the Exchange Team blog and called out a number of new features: support on the 64-bit versions of Windows Server 2008 and 2008 R2; support for in-place upgrades from the Exchange 2010 RC to the 2010 RTM; and co-existence with Exchange 2007 and 2003 servers.

The co-existence with Exchange 2007 will require Service Pack 2, which Atalla said would ship later this month.