For those who want a Windows 7 PC, you are on the clock!

In February last year, Microsoft said that it would give a one year warning of when systems with Windows 7 preinstalled would no longer be available from OEMs. That time has finally come to pass. As spotted by Ed Bott, there's now a date after which Windows 7 OEM preinstalls will no longer be available: October 31, 2016.

That same date will also apply to Windows 8.1. Windows 8 preinstalls will end a few months earlier than that, June 30, 2016. This means that after October 31 next year, the only version of Windows that will be available on a new system from a PC builder will be Windows 10. Right now, OEMs can still offer Windows 7 Professional (though not any of the other versions), Windows 8, Windows 8.1, and Windows 10.

Windows 7 will remain supported until January 10, 2020. It left mainstream support earlier this year, so it's no longer eligible to receive non-security fixes or extra features but still has many years of security updates.

This is a significant consolidation, and it will mark the first time since the days of Windows XP that OEMs are restricted to only selling systems with the current, latest version of Windows. Throughout the lives of Windows Vista, 7, 8, and 8.1, it was possible to buy systems with old Windows preinstalled. This made it easier for companies to stick with Windows XP during Windows Vista's life or Windows 7 during Windows 8 and 8.1's lives. That further entrenched the fragmentation of the Windows installed base, something that Microsoft is striving to reduce with Windows 10.

Corporations with Windows 7 deployments that they want to stick with and Software Assurance licenses won't need to worry—they'll still be able to use Windows 7, courtesy of the downgrade rights that come with their agreements. For everyone else, the countdown to the end of Windows 7's presence has begun.