Earlier this morning, Bernardo Caldas, GM of Windows Commercial Marketing, made a surprising announcement:

Windows is committing to a predictable twice-per-year feature release schedule, targeting September and March of each year, aligning with Office 365 ProPlus. The next Windows 10 feature update will be targeted for September 2017.

Each Windows 10 feature release will be serviced and supported for 18 months. This is consistent with our current Windows 10 approach, but adds further clarity and predictability to organizations by aligning with Office 365 ProPlus.

That’s a significant turning of the update screws. For the past three Win10 versions (er, “feature updates”)—1511, 1607, 1703—Microsoft’s been able to churn out new versions every eight months. Now the devs are officially on a six-month upgrade schedule, with the next version of Win10 due in September. Get used to seeing “version 1709.”

The new 18-month support limit turns the screws on IT departments. The original Windows 10, released on July 29, 2015, will receive its last security patches next month, probably May 9. That would be 650 days after its release. We don’t yet know when version 1511, released Nov. 10, 2015, will die. An 18-month clock would turn the lights off next month, while 650 days would keep it ticking until August.

Windows 7 and 8 both lasted about a decade. Just sayin’.