Last night I dutifully updated my new iPhone 8 plus to iOS 11.0.2. This morning it froze up after I checked my weather app. No response to any touches.
Of course, I can't be sure this was due to 11.0.2, since iOS 11.0.1 is causing problems. Regardless, I called Apple Support because i couldn't restart the phone.
My previous phone was a 6 +. I guess I should have realized that the restart process might have changed over the past few years. So here's how you restart an 8 plus:
(1) Press the up volume button on the left side
(2) Press the down volume button on the left side
(3) Press and hold the sleep button on the right side
It took several seconds for the Apple logo to show up, so you might need to hold the sleep button for a while. Anyway, after my phone restarted things seem to be back to normal.
The Apple Support person said that another iOS 11 update should be out soon to fix the problems with the current version.
I'm not sure what the lesson is. I like the idea of updating iOS ASAP to get new features and fixed problems. But sometimes new problems are produced by an update.