If Apple succeeds, it will allow the company to roll back changes that have already started to shift the economics of app development. Developers including Amazon and Spotify have been able to update their apps to avoid Apple's commissions and direct customers to their own website for payment.
Prior to the ruling, Amazon's Kindle app told users they could not purchase a book in the iPhone app. After a recent update, the app now shows an orange "Get Book" button that links to Amazon's website.
Epic also plans to introduce new software to allow app and game developers to easily link to their websites to take payments.