Another issue that makes OS version interoperability and Microsoft interoperability so difficult is that the rules, and the interfaces, constantly change. And not just in small ways.
For example, Microsoft’s Cloud Filter File System Minifilter suddenly started using an Extra Create Parameter with the ID GUID_ECP_ATOMIC_CREATE. This ECP was introduced in RS1 or RS2 but wasn’t used by OneDrive until sometime during RS4. And even when they started using it, the feature was never meaningfully documented. So, as FESF developers, we’re forced to wait to see how this feature is used in the real world. The result? An interoperability problem until we can “catch up” to Microsoft’s implementation changes.