I'd say you are seeing development tradeoff's that they are having to make. Likely code bases, like the one for OneDrive sync, is shared across multiple versio

I'd say you are seeing development tradeoff's that they are having to make. Likely code bases, like the one for OneDrive sync, is shared across multiple versions of Windows. That comes with tradeoffs though as newer versions of Windows might have features which are utilized to gain functionality, security or reliability. Then to support the older OS's the team tries to implement similar limited functionality but it isn't as thoroughly tested as the OS likely. Not to mention, think of it this way, if say 70% of your clients are on Windows 10, you'll probably optimize testing and features around that, not anything prior. I highly doubt this is done specifically to force people to upgrade, or to screw their older versions of Windows. And I am sure more then once a developer or product manage has said, well if they don't like that they can upgrade Windows. If you have ever written a client deployed application you have likely said it too.