There's two paths they can go down:
1. Accept that there is a sizable chunk of the user base (most probably application developers) that will continue to use Windows 7 (maybe 8.1) and remove the update blocks on these OSes. They'll get some bitching from people who felt they should have done that right from the start, but it will be short lived and life will go on with the reluctant acknowledgement that Microsoft actually listened to their customers and developer community.
2. Get into a legal and software battle with Zeffy, trying to sue him into oblivion for violating the license agreement as well as putting in "patches" to nullify the stop-update blocks. The development community will endlessly complain that builds, on older hardware because they want to do development on OSes that spy on them and provide a window into their product development, will take longer with libraries that are not fully reflective of the latest (graphic) hardware which means they'll start looking for other platforms to develop for. The bitching will be continuous with may development houses looking towards greener pastures for development programs and Microsoft's share in the marketplace will continue to decline.
I'm betting the Microsoft will take option 2.