They just shipped Unity 4.5 this week — so unless there are any more delays, the new UI system will ship in the next (and likely final) major patch before the release of 5.0.

Unity 6 Preview includes new features to make XR development easier, including ‘Composition Layers’ which can significantly increase the quality of text, UI, photos, and videos in XR. PC VR Quest ...

UI Interaction (VR) The same kind of laser pointer used for object selection can also be used for UI interactions. This means that the built-in Unity UI system that developers are already used to ...