title: How can I get Xcode working on my Mac Sierra (10.12.6)
body: <p>I seem to have gotten stuck in MacOS / Xcode purgatory.</p>
  
  <p>I'm on OS Sierra/10.12.6.</p>
  
  <p>When I try to update, I get a warning, that there's an issue with upgrading vs DisplayLink and so it cannot be done.</p>
  
  <p>That directly conflicts with Xcode which (as of now, on App Store) only works on 10.13.2 or later.</p>
  
  <p>I cannot find a place to download an earlier version of Xcode.
  I cannot upgrade to High Sierra.</p>
  
  <p>How can I get this happening?</p>