This article suggests that the cutoff date for free upgrades was only ever a marketing ploy:
Of course it was, What better way to get people to react without thinking then to put a deadline on something. It was never intended to actually stop just make people make a rash decision to upgrade without thinking. BTW as I posted in another post its not just free upgrades. If you install Windows 10 fresh and use a Windows 7-8.1 Product key during the installation it will accept it as though it is a Windows 10 key and will continue the install with whatever version the key belongs to (Win 7 Pro key installs Win 10 Pro) and so on.
Well if you think about it, since they never gave out Windows 10 keys for those upgrading to a free license, there was no other option but to support this approach. Ever since they added activation to Windows XP they had to make the promise that people with a key could use it to re-install their system from fresh. This is just the evolution of that… First the machine will attempt to find the license entitlement on the activation server, but if that fails, it can still use the key for a previous version of Windows.
Agreed, they realized that they implicitly needed to continue this from a legal licensing standpoint based on all of the Win10 free upgrade promises they made.
That is true but I believe it was Windows XP or maybe Windows 7 its hard to remember that only allowed a certain amount of reinstalls before the key would begin to stop working, granted all it took was a call to Microsoft or their automation service and you could get the PC reactivated but that is pretty much the same now with Windows 10. Even if there is an issue due to say replacing a main part of the system like the motherboard and the activation server no longer recognizes the system all you have to do is use their automation service and explain that and it gets reactivated. I simply believe that Microsoft is getting out of the game of Operating Systems and so it only makes sense that they want to get everyone on 1 product to make their job easier. About the cloak and dagger I believe that has more to do with the companies producing the PC’s and the sellers still trying to profit off of “It comes with Windows 10” but this is all just theories. The important part is that those who would believe they are out in the cold and going to have to spend a lot of money to upgrade from Windows 7 to 10 come next month can actually get it done right now with their current key for free. Like it or hate it, it is the direction that the OS is going, hopefully people don’t try to ride it out on OS’s no longer being updated and instead move over to Windows 10 or begin a new journey learning one of the many great Linux distro’s available.