Microsoft's Open License customers will receive Exchange 2003 on Friday, a few months before it becomes generally available. This newest version of Microsoft's messaging server was released to manufacturing in late June. It will be made generally available sometime in October at an official launch event, sources said. Open License is a software volume-licensing program for any customer that purchases at least five licenses. Microsoft officials declined to comment on the release dates but continue to say Exchange 2003 will be available later this year.

Customers using Exchange 2003 will initially use Outlook XP as a client. Outlook 2003 won't be available until at least mid-September but will be included in the final packaged product. Open License customers who use Exchange 2003 early will need to order a new client separately when it becomes available. Exchange Server 2003 promises several improvements over Exchange Server 2000. It adds features for better Outlook Web access, mobile and wireless support, some antispam capabilities and improved integration with Windows.