Microsoft is recommending that users who still run NT 4.0 Server should migrate to Windows Server 2003. As an incentive for customers who still have NT 4.0 servers running, Microsoft is offering a bespoke paid for 'custom' service to help companies migrate to the new platform. For those companies that need more time to migrate, Microsoft will also provide a paid for service to help with 'critical' and 'important' security issues that arise. Microsoft says that originally the plan was to offer the paid service only to the end of 2005 although, due to customer demand, this will be extended through to the end of 2006.To obtain prices for the premium services, NT 4.0 server customers should contact their Microsoft account representative.Microsoft has also announced that from January 2005, Microsoft Exchange Server 5.5 will begin its last year of extended support, and will enter 'custom' support on 1 January, 2006. As with NT Server 4.0 the custom service will last for two years until the beginning of 2008. Throughout 2005, Exchange Server 5.5 customers will continue to get free security updates. However to get non-security hot-fixes they will need to buy the Extended Support programme.