Windows 10 upgrade is still free if you have a valid Windows 7 or 8.1 product key

[Windows Central]

People who still want to get Windows 10 for free can take advantage of a loophole that allows users to get the OS if they already have a valid product key for Windows 7 or 8.1.

Full story from the WindowsCentral blog...

 

[Bryan Gislason]

Do you need to remember the product key or will it just automatically work?