Most people that I'm aware of running Xiaomi devices and MIUI with android 7 based rom are having issues with Hi-res. Will there be any fix for these roms down the line? (No rush obviously).
Thought I should also mention when running Epic Rom (MIUI 9 android 7) on my Xiaomi Redmi note 3 pro, the Hi-res failed to work. However I was able to partially get it to work by adjusting the build.prop by following this guide: https://forum.xda-developers.com/mi-4c/general/enabling-hi-res-playback-nougat-roms-t3666792. I was only able to enable 16bit at 192Khz, not 24/192.
side note: ( thanks utahman1971, seems I missed that. )