Usually, you'd activate Windows 11 (or 10) using the Settings app to enter the product key. However, if you're in an enterprise environment and you have a specific type of activation key, you can also ...

The option to sign up for an ESU subscription is available to any PC running Windows 10, version 22H2, Home, Professional, Pro Education, and Workstation editions, with the latest update installed.

At least for now, though, it seems like this change will only apply to future Windows versions. We were able to activate a fresh Windows 11 Pro 22H2 install with a Windows 8 Pro product key as of this ...