Apparently the rule is now that you cannot have any app related to a paid web service, unless you allow the user to subscribe through the App Store, and give Apple 30%. No matter if you provide links to your site or allow signing up in the app.

I wonder if this would still apply if you provide an open source version of your app, but also a paid service for that same open source app?

I’d like to think Apple gets punished for these mafia tactics, but realistically I guess there’s litte chance of that, unless the EU intervenes. For all his swagger, Trump is unlikely to even understand the issue at hand.