Thanks, I'll try that.I had a similar issue with an iPhone 5 (on Verizon) after the initial iOS 10 update. Go to settings> about. Leave that screen open for a little and see if a carrier update message shows up. I've found that carrier updates tend to be more common after iOS updates that are supposed to fix connectivity issues than they are with non-connectivity updates.
I have a 7+ and my wife has a 7 on AT&T. Signal on 10.0.2 was just fine, had no issues. But 10.0.3 just stinks.
At home with AT&T, we live close to a tower, and prior to .3 and also with 9.3.5, we got full bars at our house. But since updating to 10.0.3 we now get 1 bar at our house. I know AT&T didn't change anything with their coverage, it's the iOS update. I am hoping when 10.1 gets released with a new carrier file that it goes back to where it was.
But honestly, I am starting to think that I should have just kept my 6s+ and my wife should have kept her 5s. It just seems that the 7 line of iPhones just have too many quirks. Other than the glitches, my wife and I HATE the new optical home button. We much prefer the older physical button.
Also I work for a major cell carrier, and the majority of my customers all HATE the new home button. I know things change in life and ya have to just deal with it, but it doesn't mean every change Apple made was for the better. Also, not to beat a dead horse, but I would much rather prefer to have the headphone jack back.