Tim Cook, Chief Executive Officer of Apple Inc., speaks during the Apple Worldwide Developers Conference (WWDC) in San Jose, California, the United States, on Monday, June 4, 2018.

David Paul Morris | Bloomberg | Getty Images

Apple said Wednesday that some apps are allowed to post a link on their websites to encourage users to sign up for a subscription.

Apple has so far banned app manufacturers from instructing users to subscribe via a website, for example to sign up for a service such as Spotify or Netflix. Instead, the developers were referred to Apple’s own billing, which accounts for between 15 and 30% of gross sales.

The rule does not apply to all transactions via the App Store. Game-oriented in-app purchases must continue to use Apple’s payment system. But so-called “reader apps”, which link to content subscriptions, can now offer a service without offering a subscription handled by Apple.

The problem is one of the main complaints from developers who say Apple’s App Store has anti-competitive practices. This includes Spotify, whose complaint was a factor in the European Union’s decision to say that Apple is violating competition rules.

Apple said the decision was made as part of a settlement with the Japan Fair Trade Commission, but will apply the new rule globally.

However, it will be some time before developers have more clarity about the new App Store guidelines. Apple’s App Store rules have not yet been updated to reflect the change, which means businesses will have to wait and read the fine print before they can make changes to their apps. In fact, people familiar with Spotify’s plans told CNBC on Thursday that they weren’t sure if the new guidelines would even apply to Spotify.

Apple declined to comment beyond its Wednesday night announcement.

– CNBC’s Steve Kovach contributed to this report.