Unfortunately I don’t have much info other than we should release it soon (unsure of a exact date but best check announcements in forums - Plex for Android - #336 by ManuelPG). However for those who can’t/don’t know how to install apks you might need to wait a bit, we don’t have control over the full process (gplay / amazon store) so for those it might still take a while!
As for the Mi box question the info I found suggest a ARM Cortex-A53 quad-core 64-bit CPU is used in both the devices! So sounds like you want the arm64v8 builds!
