neowin[.]net/news/you-can-no-longer-activate-new-windows-11-builds-with-windows-7-or-8-keys/
devicepartner.microsoft[.]com/en-us/communications/comm-windows-ends-installation-path-for-free-windows-7-8-upgrade
While Microsoft's offer of a free upgrade to Win10 from Win7 & 8 officially ended July 29, 2016, that free upgrade, or using a Win7 or 8 key for Win10 & 11 activation still worked, at least up to September, 2023. On September 20, 2023, Microsoft gave notice that's coming to an end. For Now, it seems that Win7/8 keys [& I assume the upgrade from Win7/8] work up to the version of Win11 after the September, 2023, Patch Tuesday updates. It's not clear yet [from what I've read] whether the change in policy is enforced starting with the latest Win11 update [with Moment 4], or if it starts with Win11 23H2, and whether or not it will be enforced for Win10.
If you've got any old Win7 &/or Win8 keys you're hanging onto, maybe planning on using them for future Windows installs, now's the time to use them, as possible, while you still can. Note: it ***may*** be possible in the future to use those keys to activate a copy of Win10, *then* upgrade that copy of Win10 to Win11, *If* Microsoft doesn't enforce the policy for Win10, so maybe don't get rid of those old keys if you can't use them right away.