A US district court on Friday has break down some of major restrictions of Apple on how its developers can collect payments within the applications.
The court order hits down a essential part of Apple's App Store money machine.
Eventually, Apple cannot ban developers from directing customers to pay outside of Apple's own in-app purchase system.
The giant firm at present charges developers commissions up to 30 percent.
Apple also bars a developer from communicating with customers via contact information that the developer can obtained when customers signed up within the app and this ban has been abolished.
The landmark case was rattled before US District Court, Judge Yvonne Gonzalez Rogers for the Northern District of California.
The shares of Apple had fell around 2.5 percent.
The order of Judge Rogers was applicable across the United States which now allows developers to put "buttons, external links, or other calls to action that direct customers to purchasing mechanisms."
The anti-trust ruling hold responsible to Epic Games. For its part, the major firm penetrates to Epic Games's plea that the iPhone is opened up to third-party app stores.
The judge stated that Epic Games has failed to exhibits that Apple is an illegal monopolist.
The ruling comes awkwardly ahead of Apple's marquee event next week on September 14 where versions of Apple's winning products are knock for revelation.
Epic Games is best known as the developer of Fortnite which is a popular video game that is played by about 400 million people across the world.
Epic made the case that Apple's fees are the profiteering tool of a monopoly formulated within the "walled garden" that was created around the the iPhone app store, software and other devices such as the iPad and iPod.
Earlier this year, the judge grilled the CEO of Apple, Tim Cook for four hours, where he admitted that allowing links within apps to other payment options would damage the firm's revenue.