Dev:Updating extensions for iOS 11

Let's collect knowledge like we did with iOS 10, iOS 9, iOS 8 and iOS 7 – paste in your notes and share what you've learned, and somebody else will organize it later. :) If you want to ask questions and share tips over chat with other developers, see How to use IRC for how to connect to #theos and #iphonedev.

'''Hey developer, you can add your knowledge here! Yes, you! Make an account and edit this page!'''