I'm getting an iOS upgrade right now. If you upgrade your iPhone or iPad, do it using iTunes, not on the device. Doing it with iTunes replaces the entire O.S. whereas doing it on the device only patches it in some cases (like this one, going from iOS 11 to 11.0.1). I've found that patches don't always integrate and work correctly. I know that downloading the 2.4 gigabyte full replacement upgrade (on iTunes) takes a lot longer than getting the 277.4 megabyte patch (on the device), but I've found that it's likely to work better. I found the same thing to be true when I was using Android. If you've already done it on the device, you can't do it over with iTunes. YMMV.