For simple BP-only projects, it’s been very straightforward so far. For C++, I don’t know the details. I just discovered this morning that 4.17 made some major changes to the headers in order to speed up compile times, details of which can be found here. https://docs.unrealengine.com/latest/INT/Programming/UnrealBuildSystem/IWYUReferenceGuide/
I suspect the new IWYU changes might be related to the BP nativization problems I had earlier.
I suppose I really need to review the release notes in more detail whenever I upgrade. That said, at least it seems like BP-only projects are quite portable, and so far, all of my game functionality only requires BP. I’ll probably only touch C++ when I get to the performance profiling stage and find issues.
Best of luck!