There was a post a week ago or so about 7.0 leaking. I installed it to try it out and noticed youtube won't play back 60fps videos without stuttering. This was a problem back when I first got the Mi Box on release day that was eventually fixed. Anyone else having this issue? I know I could just go back to 6 but having working CEC kinda trumps it right now.
With the 7.0 beta are you also seeing a lack of 1080p / 60 fps and a lack of 4K entirely?
I think the issue issue might be a lack of VP9 playback with these newer versions of the firmware. It could be as simple as YouTube not recognizing the Mi Box with new firmware as a known device and therefore failing to 'authorizie' the Mi Box to receive VP9 video.
720p 60fps is the maximum resolution that youtube offers 60fps MP4 videos at. At 1080p, 30fps is the maximum Youtube encodes MP4 at.
What's really strange though is that the Mi Box hardware would struggle to play 720 60fps MP4 from within the youtube app.