How to get iOS11 app on Testflight?

I am trying to upload a iOS11 app to iTunesConnect (Testflight) but can't succeed any longer. Is this not possible anymore?

tried:

  • XCode 9 beta 4: WHen uploading I get the error that I need to use a public release of XCode. I haven't had this error before.
  • XCode 8: Cannot compile due to use of ARKit.
How to get iOS11 app on Testflight?
 
 
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