iPhone User Guide for iOS11
iOS 11 support for iPhone device with a 32-bit processor: specifically the iPhone 5, iPhone 5C, and the fourth-generation iPad. It is the first version of iOS to run exclusively on iOS devices with 64-bit processors, here iOS 11 for iPhone list:iPhone 5S
iPhone 6
iPhone 6 Plus
iPhone 6S
iPhone 6S Plus
iPhone SE
iPhone 7
iPhone 7 Plus
iPhone 8
iPhone 8 Plus
iPhone X
iOS 11 problem
iOS 11 users reported iOS 11 problem that quickly typing in an equation in the built-in iOS calculator app gives incorrect answers, most notably making the query "1+2+3" result in "24" rather than "6". Analysts have blamed an animation lag caused during the redesign of the app in iOS 11. The iOS problem can be worked around by typing the numbers slowly, or by downloading alternative calculator apps from the App Store that do not have this iOS 11 problem. With a large amount of bug reports filed, Apple employee indicated on Twitter that the company was aware of the issue for iOS 11.2 fixed the issue.
iOS 11 App features
Messages
App Store
Maps
Photos
Podcasts
Notes
Files
Safari
Developer APIs
Update your iOS to the latest iOS now available iOS 11.3 soon will release iOS 12