Microsoft on Wednesday added nearly 200,000 testers to its Exchange 12 beta program as it works toward a scheduled release of the software at the end of this year.The Beta 1 of Exchange 12 was first released in December but was sent out to only 1,400 partners and customers as part of a private beta. On Wednesday, Microsoft made the Beta 1 code available via download to subscribers of the Microsoft Developer Network (MSDN). The company also is sending out the beta to TechNet subscribers in the mail for delivery in the next week or so, according to Microsoft.The code is the same that was shipped in December but with a few bug fixes included.Beta 2, which will be a public beta, is still slated to ship mid-year, according to Megan Kidd, senior product manager for Exchange marketing. Kidd said it is still too early to say if Beta 2 will be feature-complete but she did say that the beta will include new features.Kidd said early feedback on Beta 1 has been heavy on the new management console, support for Monad, the new command line shell, and on unified messaging with integrated voicemail and fax.Microsoft also is highlighting the Local Continuous Replications and Cluster Continuous Replication, which provide users with a real-time copy of their messaging store for quick recovery from disk failure.The final release of Exchange 12 is expected to come no later than the early part of 2007, according to Microsoft officials.Beta 1 of Exchange 12 is focused on three sets of features: administration, access to the inbox from various sources, and compliance.Exchange 12 is being built around the concept of server roles that will allow administrators to configure any combination of five roles when they deploy the server.The roles include unified messaging; edge transport, which is a gateway for the edge of the network; hub transport, which is the message transport agent and the primary way to secure internal mail traffic; mailbox role for storage; and the client access services role, which is a middle tier to support mobile devices and Outlook Web Access.In addition, Microsoft has rewritten the Exchange System Manager, which will use the roles for operational management. Microsoft also has added a scriptable command line shell based on its Monad technology. Users could write scripts in Exchange 2003, but they had to use complex Visual Basic scripting.For the inbox, Microsoft has added support for a unified mailbox including voicemail and fax. Exchange 12 will include speech recognition software so that users can call into the server and retrieve or send mail. Outlook Web Access also is redesigned for Exchange 12 and will feature improvements in group calendaring and scheduling.On the security front, Microsoft is adding a new anti-virus API that will allow for deeper content scanning including attachment filtering.