Apple starts allowing some apps to link outside App Store for sign-up

$Apple (AAPL.US)$ has loosened some restrictions in its App Store, allowing certain apps (including $Netflix (NFLX.US)$ and $Spotify Technology (SPOT.US)$ ) to allow sign-up links that point outside Apple's store.
That move fulfills a plan it made to close an investigation by Japan's Fair Trade Commission.
The change allows developers of "reader" apps - Apple uses this term for apps that primarily provide digital content including "magazines, newspapers, books, audio, music, or video" - to link to the developer's own website so that users can create or manage their account outside of the app, including billing.
Apple has previously allowed the apps to take billing outside of its own in-app purchase system, but not to actually bill users within the app, or link out to a website for such management.
Other reader apps (and Apple rivals) that would be affected include Hulu ( $Disney (DIS.US)$ , $Comcast (CMCSA.US)$ ) and $Amazon (AMZN.US)$ family of apps including Kindle, Prime Video and Audibble.
It's a small change but a notable one, particularly in light of $Alphabet-A (GOOGL.US)$ 's move to let app developers in its Play Store to use their own billing systems rather than Google's.