When I first took a cursory look at the Oreo update on my MiBox MDZ-16-AB I was dismayed at the seeming lack of critical settings.
There is a new, important feature called Droid Settings that gives access to those missing settings. It appears on the home screen.
Here is a screen capture of the major elements that are covered under Droid Settings. Please note, my updated MiBox is currently connected to a 1080 res projector. Your options may differ based on your connected screen.
HDR, finally.
Unless it's a pixel shifting projector, 8 million pixels (4k) wont appear even if the settings is 2160p. Most projectors will simply downscale it to 1080p