Apple’s “Sign In with Apple” login system will no longer work with Epic Games accounts as soon as September 11th, Epic said today. The new restriction is another casualty of Apple and Epic’s ongoing spat.

If you currently use “Sign In with Apple” for your Epic account, Epic says you’ll need to update your account with new login credentials before September 11th to retain access. Epic has put together a guide on how to make that update if you need to do so. Epic also says that it may be able to recover your account manually after the “Sign in with Apple” option goes away, but you’ll have to contact the studio directly.

Apple requires developers to use its single sign-on system if they offer any other third-party options and want their apps in the App Store — presumably a driving factor behind Epic offering the service as a sign-in factor in the first place.

Epic tweeted about the upcoming change on a number of its Twitter accounts, including the main Epic Games account, the Fortnite Status account, and the Unreal Engine 5 account. That wide breadth is probably because Epic Games accounts span more than just letting you play the studio’s smash hit Fortnite — they’re also used to log into the Epic Games Store, access Epic’s developer portal, and more.

It’s also worth noting that Fortnite, which is available across many platforms, is most popular on iOS. Epic said in a legal filing last week that it has 116 million registered users on iOS, which accounts for nearly a third of the 350 million total registered Fortnite users. If even a fraction of those users rely on “Sign in with Apple” and don’t change their login credentials in time, there’s a chance that many people could lose access to their accounts.

Apple banned Fortnite from the App Store on August 13th when Epic introduced an in-app payment system that violated Apple’s rules. Since then, the two companies have been in a legal battle over the future of Fortnite in the store as well as Epic’s standing with Apple as a developer. Epic won a temporary restraining order on August 25th that prevented Apple from terminating Epic’s developer account used in conjunction with its Unreal Engine, but that order didn’t force Apple to bring Fortnite back to the App Store.