title: Code migration from Swift 2.x to Swift 4
body: <p>We have big enough project which is built up with Swift 2.x and now Apple has just released Swift 4 so to move forward for latest version of Swift which path we can choose...</p>
  
  <p><strong>Do we need to migrate our code to Swift 3 first? Or we can directly migrate our code to Swift 4 using Xcode 9?</strong></p>