Microsoft will retire Exchange Server 5.5--along with support for the product--at the end of this year, it said today. The company recommends that users upgrade to the latest version.

Microsoft urges customers who are still running Exchange 5.5 to upgrade to Exchange Server 2003, a more secure version of the messaging and collaboration server product. You can find information about upgrading to Exchange Server 2003 here.

User Numbers Dropping

According to Microsoft, the number of Exchange Server 5.5 users dropped by about 40 percent over the past year, evidence that customers have been upgrading in anticipation of the product's phase-out.

Microsoft also reminded customers that Exchange Server 2000 will move out of mainstream support and into extended support at the end of 2005. Mainstream support includes free incident support, security updates, and nonsecurity hotfixes. Once Exchange Server 2000 moves into extended support, customers will have to pay for support and non-security-related hotfixes, according to Microsoft.

The software vendor won't accept requests for warranty support, design changes, or new features during a product's extended support phase. Extended support applies only to business and development software products--not to consumer, hardware, or multimedia products.

Microsoft provides further information about its product support policies here .

The company plans to release the next version of Exchange (code-named Exchange 12) to manufacturing late in 2006.