When changing the bundle identifier on my iOS Xcode project to match the bundle identifier of the app I've published, Xcode says this:
Failed to register bundle identifier
The app identifier "com.bookup.chessopeningswizard" cannot be registered to your development team because it is not available. Change your bundle identifier to a unique string to try again.
I can set it to any other bundle identifier and Xcode is okay.
I believe I need to set it to the app identifier of the published app because I'm creating a new version of the app.