Microsoft is "ramping down" production of the 5-year-old Windows NT 4.0 operating system and will no longer sell volume licenses for the product, the company said Tuesday.
The OS will still be available through retail outlets, said a Microsoft spokesman, and volume users will be covered by the Windows 2000 volume license.
Users with an installed base of NT 4.0 machines will be able to extend their licenses by buying the Windows 2000 volume license and "exercising downgrade rights" to keep using the older system, said the spokesman.
Microsoft's spokesman said he could not confirm whether this would be more expensive than current licenses, nor whether the license conditions would differ.
Support for the OS will continue, he said, and regular life-cycle guidelines will be issued to keep users up to date with developments.