The company said that the three key changes to the App Store review guidelines support new features in upcoming OS releases, better protect customers and help apps go through the review process as smoothly as possible.

Among the changes, developers are allowed to communicate with their customers about other payment methods available outside their app.

Another new guideline says that apps may request customer information like name and email, but the request must be optional for the user and shouldn't prevent them from using the app.

"Developers cannot use information obtained within the app to target individual users outside of the app to use purchasing methods other than in-app purchase (such as sending an individual user an email about other purchasing methods after that individual signs up for an account within the app)," Apple said in one of the changes.

"Apps may request basic contact information (such as name and email address) so long as the request is optional for the user, features and services are not conditional on providing the information, and it complies with all other provisions of these guidelines, including limitations on collecting information from kids."

Apple said that in-app events are timely events that happen within your app.

"To feature your event on the App Store, it must fall within an event type provided in App Store Connect. All event metadata must be accurate and pertain to the event itself, rather than the app more generally," the company said.

"Your event deep link must direct users to the proper destination within your app."

Both Apple and Google have reduced commission fees for developers from 30 per cent to 15 per cent.

Apple offers reduced 15 per cent subscription fees from day one, but that's limited to developers who are part of its App Store Small Business Program, which is available to those who earn up to but don't exceed $1 million in a calendar year.