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.

—Users can open Unity Editor from the RPG Maker Unite UI anytime they need it. —It is possible to have both editors side by side, making modifications while confirming each other simultaneously.

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.