Youtube App 4k and HDR support?

Unfortunately after checking multiple sources it seems that the YouTube app on the One S does not currently support 4K. The One X app received an update on Dec 11, 2017 which allows 4k content (HDR not included) but the app for One S is still in development.
Sorry for the confusion. Even I had to do a little research.

I've started having this issue on my Xbox one x , non Scorpio edition . Watching GN will do it and also Tech Yes City (but his is 30p @4k) . Watching the same videos on my S (the 30p ones play in 4k) , I will not get this issue . I'll watch to see
what the VP9 is it to see if it's the same . YouTube updated it's app on my Hisense 4k HDR10 tv & either they removed the HDR support or Hisense did . I no longer have HDR on it , yet the signal shows VP9.2 (which should be HDR) . All my issues seemed to occur
at the same time , which makes me think it's YouTube messing around .

It's definitely has to do with the updates to YouTube app. Google is migrating away from HEVC and adopting VP9 due to licensing issues and VP9 is open source. I think Google needs to update the YouTube apps on different devices to support VP9 in better manner.
Also, as I mentioned before, Google is deliberately throttling bitrate of YouTube videos on some devices, but we don't know what devices they are.

I've started having this issue on my Xbox one x , non Scorpio edition . Watching GN will do it and also Tech Yes City (but his is 30p @4k) . Watching the same videos on my S (the 30p ones play in 4k) , I will not get this issue . I'll watch to see what
the VP9 is it to see if it's the same . YouTube updated it's app on my Hisense 4k HDR10 tv & either they removed the HDR support or Hisense did . I no longer have HDR on it , yet the signal shows VP9.2 (which should be HDR) . All my issues seemed to occur
at the same time , which makes me think it's YouTube messing around .

I can verify this issue...Netflix UHD does not work on Xbox One S. I have a Vizio M55-D0 with the latest firmware enabling HD10 support. My TV is now recognized by the One S video settings as 4K HDR capable. I am able to enable HDR support and it works beautifully
with the Blu-Ray app (Mad Max 4K Blu Ray playing 4K, 24fps, HDR as verified by the Vizio settings app). However when I start Netflix, the screen flashes, colors mute, and video fails to switch to HDR or 24fps. Netflix app is clearly broken right now for HDR.
If I switch HDR off on the One S, Netflix app is fine, plays 4K correctly, colors are fine obviously no HDR.

so, does it use codec TVs codec or console's codec ?