iOS 11 GM is completely unusable on my iPhone 6S 64gb. Stock apps crash like settings, notes and the app store, as well as reddit, tinder, snapchat, facebook and so on. Sometimes it even goes all black with a dashed circle before it reloads the phone where I have to type the code. It's obvious to me that apple has focused on making it work on the iPhone X before any other device. Edit: Restoring without erasing contents didn't help before, so I did what others advised me and restored and erased all contents and set it up as a new device. It seems to have fixed the issue.