support.microsoft[.]com/en-us/windows/windows-8-1-support-will-end-on-january-10-2023-3cfd4cde-f611-496a-8057-923fba401e93
Those still on Win8.1 will start seeing nag messages soon. Microsoft is not going to offer extended support. An interesting note regarding the Q & A on the Microsoft page:
Are there free options to upgrade to Windows 10 or Windows 11?We do not currently offer free upgrade paths from Windows 8.1 to either Windows 10 or Windows 11. If you want to purchase a copy of Windows 10 or Windows 11, please see links above or contact a retailer to find out about options. Note: the upgrade from Windows 10 to Windows 11 is currently free.
TO date, people including well-known journalists like Ed Bott are reporting Win8.1 keys work for Win10 & 11, as long as you're not trying to use a single-use OEM license from one PC on another. I used a Win8.1 Pro key to activate Win11 on my wife's PC after swapping the motherboard/CPU. It could be that Microsoft's activation servers are set to let one-off infractions of their rules slide, or maybe they never turned off the free upgrades when the original term was over? Assuming Microsoft doesn't go back and change their wording, e.g., if there's a backlash, it probably wouldn't hurt to perform the upgrade to Win10 sooner rather than later. Thousands of people trying to use Win8.1 keys in January 2023 might be cause enough for Microsoft to block them.