Under the new policy, Microsoft's business and developer software will get regular support, referred to by Microsoft as "mainstream support," for five years from the software's general availability date. After that, extended support, consisting of hotfixes and hourly support, will be offered for a fee for two years. Security hotfixes will continue to be free throughout the extended support period. At the end of the extended support period, Microsoft will offer online self-help support for one year, bringing the entire support period for business and developer products to eight years.

Last December, Microsoft disclosed that mainstream support for Windows NT 4.0 would end Dec. 31, 2002, fee-based support would be extended through Dec. 31, 2003, and security and online support would extend to Dec. 31, 2004.

According to the software support schedule posted on Tuesday, Microsoft is largely carrying forward the Windows NT 4.0 support commitments it made a year ago, even though they are slightly more generous than Microsoft's new policy. Mainstream support for Windows NT 4.0 will still last through Dec. 31, 2002, which is six years instead of five years after the general availability of Windows NT 4.0. Extended support for Windows NT 4.0 will only last one year instead of two years, until Dec. 31, 2003. The date is consistent with the date give out by Microsoft in 2001 and consistent with the seven years of combined mainstream and extended support Microsoft is promising in its new plan. It was not immediately clear if Microsoft would honor its 2001 commitment to provide free security hotfixes until the end of 2004, or if it would cut off the free security hotfixes at the end of 2003, which would be consistent with the new policy.

The Dec. 31, 2003 deadline for mainstream support of Exchange Server 5.5 provides an important cutoff date for customers still contemplating or struggling with a move to Exchange 2000, which requires an Active Directory deployment. Extended support for Exchange Server 5.5 lasts through Dec. 31, 2005.

Mainstream support for SQL Server 7.0 will end on March 31, 2004, with extended support wrapping up March 31, 2006.

Windows 2000 and Windows XP also got deadlines. Mainstream support for Windows 2000 ends March 31, 2005 and extended support is over March 31, 2007. There's an exception for Windows 2000 Datacenter Server, which shipped six months after the other versions. Mainstream support for the high-end server operating system lasts until Dec. 31, 2005; extended support goes through Dec. 31, 2007. Windows XP, which shipped one year ago will see mainstream support retire Dec. 31, 2006. Extended support for Windows XP Professional lasts until Dec. 31, 2008.

Microsoft's entire roster of products and their support end dates are available here: http://support.microsoft.com/default.aspx?scid=fh;en-us;complifeport