Microsoft is set to end its TechNet subscription scheme. Started in 1998, TechNet subscriptions gave IT professionals perpetual licenses to Windows client and server operating systems. Though these licenses were technically only authorized for evaluation purposes, many used them as cheap Windows licenses for personal machines.

First reported by Ed Bott, Microsoft today e-mailed TechNet subscribers to inform them of the changes. Both new subscriptions and renewals will remain on sale until August 31, 2013, with activation of subscriptions supported until September 30, 2013. With most subscriptions lasting one year, TechNet subscriber downloads will cease to work on September 30, 2014.

For volume license customers, TechNet subscription benefits will be available for the duration of the volume license agreement.

In addition to illicit production use, there have been reports of TechNet license keys being sold without disclosing their evaluation nature, leaving their buyers unwittingly exposed in the case of a software audit.

To justify the change, Microsoft said that users wanting evaluation copies of its software had shifted to freely available time-limited trial copies. That caused a decline in usage of these paid evaluation licenses.