Available now (UK):
"Offer exclusive to PS Plus members from 00:00 (GMT) Nov 12th to 23:59 (GMT) Nov 15th before then being available to all customers from 00:00 (GMT) Nov 16th to 23:59 (GMT) Nov 26th 2018"
Just use anything other than TV speakers please people!
It's a nightmare making a mix for a game where it sounds good on TV speakers, they are almost universally terrible. Use headphones, a soundbar, stereo speakers or a full surround system, but please don't listen to games (or anything for that mater) via TV speakers.
ThreadXbox One X Enhanced Games: All Titles, Platforms, and Details
don't forget to add... 60fps, Resolution TBC30fps, Resolution TBC
Final resolutions won't be locked until much nearer release when all optimisation work has been completed, but it'll output a 4K OSD in both modes.
For clarity all of the dev work is done in tandem on both PS4 & XB1. Both get submitted to 1st parties on the same date, but the fact of the mater is that the certification process on one platform for submissions and releases takes longer.
We could align the updates by delaying one, but I'd rather not make one group of players wait because of external logistics and processes.