If you previously had Facebook or Messenger installed on the phone it's possible...

Im_Mr_Manager · on April 11, 2018

AFAIK device uuid has been unique to device+app for at least 2 years now (iOS).

zer00eyz · on April 11, 2018

device + app having a unique UUID has been going on longer than that.

3 years ago uber got popped for this:

I can tell you that fingerprinting is still possible today.

aplummer · on April 11, 2018

It’s company not app on iOS, you get a new one if you delete every app from one publisher