EES
This means that the OS can be upgraded (changed to a higher version) only if it is already running a Windows OS.
If your PC already has a Windows OS when you buy it, you are eligible.
In the case of a Mac, the upgrade can be applied as an OS that runs on virtual environment software or boot camp that can run on a Mac.
Downgrading the OS is also possible, but not recommended.
EES - Windows OS
This means that the OS can be upgraded (changed to a higher version) only if it is already running a Windows OS.
If your PC already has a Windows OS when you buy it, you are eligible.
In the case of a Mac, the upgrade can be applied as an OS that runs on virtual environment software or boot camp that can run on a Mac.
Downgrading the OS is also possible, but not recommended.