Yes they did. If they deliver an OS upgrade and a bunch of apps stop working, the user will blame the OS upgrade regardless of the real reason. Raymond Chen (from MS) covered this well on his blog
This is software engineering 101, really, and the reason we have the concept of private interfaces in the first place: you bloody well expect first party developers to be able to change the private parts of the interface with abandon, knowing that third-party consumers of those interfaces will not break because of those changes.
http://blogs.msdn.com/b/oldnewthing/archive/2003/12/24/45779...