title: Is it possible to use Swift 4.0 (4.0.3) with XCode 9.3?
body: <p>I'm trying to upgrade to XCode 9.3 so that I can run my app on an iOS 11.3 device, but I'm having some issues.</p>
  
  <p>My app has up until this point been built in XCode 9.2 with Swift version 4.0.3. I would like to keep the app on Swift 4.0.3, but I can't seem to choose that option in XCode.</p>
  
  <p>I have toolchains set up to point to: Swift 4.0.3 Release 2017-12-05</p>
  
  <p>When I go to Build Settings -> Swift Language Version I have only three options: Swift 3.3, Swift 4.1, and Unspecified. None of these are working for me.</p>
  
  <p>How can I build and run my app on a device using Swift 4.0?</p>