update to iOS 13 - phone says: vers. 12 is "up to date" but Amazon wants vs. 13
I'm trying to update my "Amazon Shop" app.
The app requires that I run iOS 13+ on my iPhone.
My iPhone 6 reports that with iOS version 12.6x the operating system is "up to date."
So I am apparently unable to update my iOS.
I have my phone set to "automatic updates" and regularly put it to "sleep" or "turn it off" plugged in at night - but still I (or it) cannot update the iOS.
All this begs the question of why the latest iOS is 15 or 16, and my iphone is "up-to-date" with 12.
Please someone advise.
Katzi
iPhone 6, iOS 12