Windows activation: upgrade win7 to win10, then downgrade to win8 ?

[hhhd1]

Windows 10 pro comes with downgrade rights to 8 pro or 7 pro.

Anyone tried upgrading a laptop that came with windows 7 pro to windows 10 pro, and then tried to install windows 8 pro with the generic key to see if it activates via MS servers or not ?

My understanding is that windows 8 and 10 use very similar activation process.

[theterminator93]

If you have a laptop that came with 7 Pro - not as a downgrade license from 8, 8.1 or 10, and if you buy a license for 10 Pro and install it, you will not be able to 'just install' 8 over top of 10 using the same key. The keys are OS specific and don't permit the downgrade automatically. E.G. you can't plug the Windows 10 key into Windows 8 and have it activate.

If you get that license for 10 Pro, which would include rights to downgrade to 8/7, you'd need to contact Microsoft to have them provide you with the appropriate product key to the OS you want to downgrade to [be it 7 or 8], then use that key to activate the downgraded OS. You'd still be able to use the key for the parent OS (10) to reinstall and reactivate it on the same device, just not at while (legally) the other one is installed as well.

When we get additional OS licenses (not through an OEM) for hardware (either to upgrade... or whatever) through MS volume licensing, we get all three keys at once. We're only legally entitled to use one instance of either of those OSes at a time - no dual or triple booting, no "three keys, three machines" type stuff.