My old android phone (has a real radio), and also a tablet (now used as an extra screen for my pc)i have both work great, but apparently they're too old for yo

My old android phone (has a real radio), and also a tablet (now used as an extra screen for my pc)i have both work great, but apparently they're too old for youtube to be installed from the playstore. Can watch what i want on yt.com, but can't have the app (and several others).