title: Use Xcode 8 with iOS 11
body: <p>I want to use Xcode 8 with iOS 11.</p>
  
  <p>should I upgrade my Xcode. However, my code can't be built by the new compiler, so I want to stay with Xcode 8.</p>
  
  <p><a href="https://i.stack.imgur.com/l84Gj.png" rel="noreferrer"><img src="https://i.stack.imgur.com/l84Gj.png" alt="enter image description here"></a></p>
  
  <p>How can I achieve that?</p>
  
  <p><strong>Apple revealed several new iOS 11 features at WWDC 2017.</strong> </p>