Microsoft has a very elaborate backwards compatibility system. They can do things like like to some processes about what version of Windows they are running on,

Microsoft has a very elaborate backwards compatibility system. They can do things like like to some processes about what version of Windows they are running on, change the behavior of particular APIs to work around application bugs, and generally inject whatever hacks and adjustments that they need in order to ensure that old or badly written software continues to run on new versions of Windows. It's glorious (lousy software continues to work while Microsoft is able to continue improving the OS) and terrible (software developers who are updating their software get shims applied and this complicates development, hides bugs, etc. https://en.wikipedia.org/wiki/Shim_(computing) https://en.wikipedia.org/wiki/Shim_(computing)