Heres how you can still get a free Windows 10 upgrade
Summary
You will not be asked for a product key, and when the upgrade is complete and youve connected to the Internet, youll have a digital license to Windows 10, which you can confirm by going to Settings > Update & security > Activation.The digital license is associated with that specific device, which means you can reformat the disk and perform a clean installation of the same edition of Windows 10 anytime.The entire "free upgrade" offer was always accompanied by language that was, to put it politely, a bit squishy.The FAQ on a separate page even calls it a "free upgrade offer extension" and pointedly notes that it is not limited to specific assistive technologies.The big question now is whether Microsoft will finally turn off the code on its activation servers that dispenses digital licenses after an upgrade from an earlier Windows version.