Android unique Id

Hi, iam looking for a unique android id, that i can use to track installations of my app, and check if they have licence when they send data to backend. So far i was using Android ID, but it seems to change from time to time, so it isnt reliable. Is there any other Id i can use, that is accessible on all androids, and it doesnt change?
Android serial seems not as solution either because, it is not on all android devices. Any ideas?

You can use this :

This seems to be the Android id, that is changing. In github repo, there are issues, that it isnt reliable.

ok than use this :

This is the plugin i used so far - device.uuid, but it changes also. These two plugins seems to do the same thing