Blog Post
Well, the release notes say "these were previously only supported for developers". That's what finally made me realize they didn't actually add anything NEW to the hand tracking support. Just the same as everyone already had who turned on developer mode. I'm a developer who is working on hand-tracked apps, so it was very disappointing. Such a pain to have to fish out the controller to exit link nicely (because sometimes, if you don't it gets in a bad state).