Apple announced Friday that it would appeal the ruling in Epic's antitrust lawsuit, which opened the door for developers to nudge app users toward the web for cheaper purchases.
Citing "unintended downstream consequences for consumers and the platform as a whole" if the ruling goes into effect, Apple also said it would seek to stay the decision pending the appeal.
Epic had already appealed the decision.
Apple charges a commission on many in-app purchases, which some developers say drives up the price users pay. Judge Yvonne Gonzalez Rogers ruled in September that the iPhone maker must allow apps to tell customers that prices are lower elsewhere, like on an app company's website.
The injunction on so-called "anti-steering practices" was due to go into effect in December but could be delayed for several months or more if Apple wins a stay.
The Epic ruling focused on in-app communications. As Apple faces additional lawsuits and regulatory pressure, it had already declared it would allow apps to communicate with users outside iOS.
In court documents that Apple provided to reporters ahead of filing, the company hinted it might seek a narrow interpretation of what's allowed by the judge's ruling, and suggested its appeal would touch on a recent Supreme Court decision that upheld anti-steering provisions imposed on merchants by credit cards with higher fees.