Old Windows Insider Preview Builds to Start Expiring
If you've forgotten to update your Insider build of Windows 10, you may be in for a rude awakening. In a blog post detailing Insider "Redstone 2" Build 14926, Windows Insider Chief Dona Sarkar noted that "really old Insider Preview builds" will start expiring.
Considering that, if you're part of the Insider program, Windows automatically updates to the latest build for you, most users won't have to do anything. However, if you've been doing something that prevents automatic updates (ex: keeping your computer offline), you should force an update sooner rather than later. Starting tomorrow (September 15), users will start being pestered by daily notifications to upgrade. On October 15, affected computers will start rebooting every three hours. On October 15, they won't boot at all.
Today's version, Build 14926, won't expire until May 1st, 2017. It introduced an experimental feature to snooze tabs in Edge, among other fixes for both desktop and mobile.
Sarkar noted that those running Build 14393, the Windows 10 Anniversary Update on the slow and release preview schedules don't have to worry about the new expiry and won't be affected.
One can only speculate, but it's possible that Windows wants to make sure its Insiders continue to test features as fast and furiously as they come, and to get as many users as possible onto the Anniversary Update (though normal users may have to wait until November).
Insiders can grab the latest update by going to Settings > Update & security > Windows Update.