I have always had this issue with my AT&T phones because I use Cricket. I use Cricket because it's cheap and I can use it on my AT&T phones. Simple enough, but there's one drawback: I have never been able to update the software. My last phone was a Nexus 6P, and I never had this issue because it was unlocked. The phone before that was a Galaxy S6 Active, and I was stuck with the Android L that came on it. I had taken the phone even before that, which was a Note 4, to Best Buy and they were able to force the update, but I don't want to have to do that every time with my G6. I am left to believe that it is a carrier issue because i'm using a Cricket SIM in a AT&T phone, but there must be some way to force the update myself. Anything helps!