The ios 11 update has caused a lot of iphone & ipad users quite a few problems. That seems to be particularly true for iphone 6 users. When I installed the initial update on my iphone 7, I noticed shortened battery life, as did many other folks. Steps can be taken to alleviate the problem. Many users, myself included, encountered problems with apps crashing, and websites freezing. After installing ios 11.0.2, and updating numerous apps, my phone and ipad seem to have stabilized. Users of iphone 6 are still reporting problems. Here's good news! You're not stuck with ios 11. Click here for instructions on removing it.

[Mashable]