Epic Games Ltd.’s lawsuit against Apple Inc. following the removal of Fortnite from the App Store has taken several new twists, the most notable among them that Microsoft Corp. filed a declaration of support.

The drama started Aug. 13 with Fortnite being banned from both Apple’s App Store and Google Play after Epic Games added support for in-app payments. Players of the world’s most popular game, which is free to play, can buy customization items such as outfits, “emotes” or short character animations, and a Battle Pass that offers additional features.

In the PC and macOS versions, players can purchase those items directly from Epic Games. But per the rules of both the App Store and Google Play, those purchases are meant to be made through each store, with Apple and Google taking a 30% cut of each transaction. Epic bypassed that requirement, the part of the terms of service of both stores that led to the Fortnite ban.

Epic subsequently filed lawsuits against both Apple and Google. The lawsuit against Apple gained the most attention given that it seeks to establish Apple’s App Store as an illegal monopoly. The lawsuit against Google differs somewhat, with Epic Games claiming that Google undertakes anticompetitive behavior. Unlike iOS, Android is not a closed shop and allows support for third-party app stores.

Microsoft joined the fray today with a declaration claiming that Apple’s decision to block Epic Games’ developer account would deal a significant blow to game makers, including Microsoft, by making them unable to use Epic’s Unreal Engine.

“If Unreal Engine cannot support games for iOS or macOS, Microsoft would be required to choose between abandoning its customers and potential customers on the iOS and macOS platforms or choosing a different game engine when preparing to develop new games,” Kevin Gammill, Microsoft’s general manager for Gaming Developer Experiences, said in the declaration.

The Unreal Engine is used by an array of third-party developers. Epic argues that the loss of its access to an Apple developer account would result in not only damage to Epic itself but also to the various companies that use the engine given that Epic will no longer be able to support it on iOS and macOS.

Today we filed a statement in support of Epic's request to keep access to the Apple SDK for its Unreal Engine. Ensuring that Epic has access to the latest Apple technology is the right thing for gamer developers & gamers https://t.co/72bLdDkvUx

— Phil Spencer (@XboxP3) August 23, 2020

“Developing a game using different game engines for different platforms may be prohibitively expensive and difficult,” Gammill also said in the declaration. “In any event, it is not as cost-effective as using a game engine that supports different platforms. As a result, game creators, including Microsoft, that are preparing to develop a game targeted at multiple platforms generally choose game engines based both on the functionality they provide as well as their ability to support development for those platforms.”

Apple has not been quiet in response, responding to the lawsuit by claiming that Epic Games itself is guilty of anticompetitive behavior. Apple alleges that Epic Games asked for an individual agreement and produced three emails from Epic Chief Executive Officer Tim Sweeney to support those claims.

“On June 30, 2020, Epic’s CEO Tim Sweeney wrote my colleagues and me [in] an email asking for a ‘side letter’ from Apple that would create a special deal for only Epic that would fundamentally change the way in which Epic offers apps on Apple’s iOS platform,” former Apple Senior Vice President Phil Schiller wrote in a declaration.

The declaration goes on to claim that Sweeney was asking permission for Epic to bypass in-app purchases and allow Fortnite players to pay it directly, as well as permission to launch a third-party app store for iPhones.

Although the accusations made by Apple are not necessarily bad, they do fly in the face of Sweeney’s public statements.

Today, Apple said Epic is seeking a special deal, but that's not true. We're fighting for open platforms and policy changes equally benefiting all developers. And it'll be a hell of a fight! https://t.co/R5A48InGTg

— Tim Sweeney (@TimSweeneyEpic) August 14, 2020

The next hearing in the case is scheduled for Monday in the U.S. District Court for the Northern District of California.

Image: Epic Games