Microsoft on Monday announced the immediate availability of Exchange Server 5.5 at a press conference attended by chairman and CEO Bill Gates. The new version of Exchange Server includes an unlimited message store, performance improvements for backups, and support for numerous Internet protocols and development tools. Exchange Server 5.5 will be priced the same as version 5.0, Microsoft officials said.

As part of the announcement, Microsoft revealed that 7.2 million Exchange clients are now in place around the world. Gates compared Exchange Server to its only real competitor, Lotus Notes/Domino.

"\[It's a\] two-horse race. The only place we are playing catch-up is in some simple groupware development," Gates said. "That is the strength that Notes has had."

You can download a 120-day evaluation copy of Exchange Server 5.5 now from the Microsoft Exchange Server home page.

During the Exchange press conference, Microsoft revealed that the second beta of Windows NT 5.0 had slipped from December 15th to the "first half of 1998." They refused to speculate when the final version would ship, but most analysts are not expecting it until the end of next year at the very earliest.

Windows 98 Beta 3, meanwhile, will ship "by the end of the calendar year." Beta 3 will be the "final beta" of Windows 98, Microsoft officials said. The final product is due in mid-1998