Originally Posted by
Deepak_HK It's not just about upgrading through ISO, I know it can be done that way, but about activation. I do not wish to revert back to Windows 8.1 if anything goes wrong.
that's what I am saying, why would you be able to upgrade and not activate? The win7 and 8.1 key carries just like WU, and detects if you have a valid windows license to activate windows 10. and just like other upgrades from WU or ISO, you will have 1 month to revert back if you want.
Also as I remember, by using ISO you would be able to choose "what to keep" about personal files and apps, or just personal files or nothing and do like a clean install. but the key always carry like any upgrade.