Apple will no longer allow users to sign into Epic Games accounts using “Sign In with Apple” as soon as September 11, 2020, Epic informed its users on Wednesday. This essentially bars Epic from using Apple’s quick login systems for users who still have Fortnite installed on their devices. Users will have to transfer their data to a separate email address before that date to retain access to their Epic user account. This marks yet another example of Apple’s control over the iOS ecosystem, as Apple and Epic are fighting in court over the future of Fortnite, and its development platform Unreal Engine on Apple-owned operating systems. Fortnite has been removed from the App Store ever since Epic Games announced its intention to bypass Apple’s in-app purchase commission rule.

Epic did say that in case a user fails to update their login credentials before September 11, they might still be able to recover their accounts, but for that they’ll have to contact the company directly. Epic has also put together an explainer on how users can shift their data to a separate email address. It is worth noting that Apple has terminated Epic Games’s App Store account following a court ruling (more on that below).

Apple’s control over its ecosystem: In 2019, Apple had introduced the “Sign in with Apple” feature which is its own single sign-in service to compete with similar ones from Facebook and Google. Apple had later made it mandatory to include this particular login system in apps that offer third-party sign in.

Apple vs Epic: This development comes just days after Apple sought damages against Epic Games for allegedly breaching the iOS contract the company had agreed to while submitting apps to App Store. Apple and Epic are currently locked in a legal battle after Epic sued Apple for booting its popular game Fortnite out of the App Store for allowing users to pay for in-app purchases directly to Epic instead of routing those payments via Apple’s mandatory in-app purchase system.

After Epic sued Apple, the latter retaliated by threatening Epic that it will cut all of its developer accounts from iOS and Mac development tools, including Unreal Engine, which is an industry standard engine used to develop and produce several games and TV shows such as PUBG and The Mandalorian. Since then, following a ruling in the case, while Unreal Engine’s immediate future looks safe, Fortnite doesn’t look like it is going to return to Apple devices any time soon. The next hearing in the case is scheduled for September 28.

*Update: An earlier version of the article incorrectly said that Apple has cut Epic’s access to third party login, when in fact, it will only stop support for its own login system. Headline was changed to reflect this. Error is regretted.