title: How does Swift 5 ABI stability affect iOS app that supports iOS 11?
body: <p>Swift 5 brings ABI stability, so iOS app written in Swift no longer need to package the swift standard libs into the app bundle. How does this affect the apps that still supports iOS 11, which doesn't have swift libs pre-installed?
  If those libs still need to be bundled into the app, what's the immediate benefits to upgrade to Swift 5 now?</p>