Apple Inc. violated a court order requiring it to open up the App Store to third-party payment options and must stop charging commissions on purchases outside its software marketplace, a federal judge said.

The changes the company must now make could put a sizable dent in the double-digit billions of dollars in revenue the App Store generates each year

U.S. District Judge Yvonne Gonzalez Rogers determined that Apple’s implementation of a 27% fee on external purchases and the display of warnings about third-party payment methods obstructed the court’s directive to permit developers to inform users about alternative payment options.