Good day Sir,
Expert iOS developer at your service. As I read from the link you post, they claim they included source for iOS, I wonder whether it is Swift or Objective C and if it is up to date as XCode has been constantly changing. If you belong to the Apple Developer Program, invite me over as dev and I'll compile and sign the app on your behalf.
Thank you so much for your time and attention.
Regards,
Raú