Microsoft's free upgrade offer from Windows 7/8 to Windows 10/11 technically ended, but the activation servers still accept valid Windows 7/8 keys. If you have an old license, you can upgrade for free legally.
: It is designed to work with Windows versions (from Vista to Windows 10/11) and Office suites (2003 through 2019). System Management Microsoft Toolkit 2.5.2 Activator 4 Windows And Office