I have an active Windows 10 key on my system with Windows 10 installed and I keep getting prompt on startup to upgrade to Windows 11.
I have ignored these upgrades since I am not sure if I decided to upgrade to Windows 11, will my Windows 10 key no longer work for Windows 10 installation and only work for Windows 11 installations going forward once I upgrade?
Best to assume Microsoft does not want you to go backwards and your key will be locked to w11
There literally isn’t a difference between a license key for Windows 10 and Windows 11 (maybe things are different in Enterprise licensing, but definitely not for Windows Home and Pro) If Windows 10 is activated on your PC, you can install either without issue.
There are VERY few usecases that warrant upgrading from W10 to W11 at this particular point in time. Unless there is some feature that is not available on W10 which is also worth it (honestly can’t think of a single one) I’d just wait until at the very least end of life support for W10 ends.
For me it was the look of 10. I just don’t like it. However, I did have to do a ton of disabling crap in 11 to get it to a minimalistic state. So much ad and copilot garbage to turn off. So much.