Can’t say about the Pencil, but I’m hopeful that the new 2048x2732 resolution “just works,” since I’m about to submit an update that claims a larger view area on iPad Pro.
My code responds to the larger pixel res; I have no iPad Pro yet for testing, but deploying to the simulator does seem to work! (Including the new mega onscreen keyboard, albeit with some InputField glitches.)
iTunes Connect says (even for my earlier Unity 5 release) that my app already supports iPad Pro, and suggests I upload iPad Pro store screenshots. I’m hoping that’s a good sign!
But I don’t see where I can specify iPad Pro launch screens (or icons for that matter); so the regular iPad splash creen just gets enlarged. And I worry that might mean my app can’t be recognized in Apple’s list of iPad Pro-ready apps.