Apple officially started allowing “retro game console emulator apps” in the App Store earlier this month, though it wasn’t clear what exactly was allowed. The first emulator app to test that new rule has already been removed.

Earlier this month, Apple updated its App Store guidelines to explicitly mention “Retro game console emulator apps can offer to download games.” However, it wasn’t immediately clear if typical emulation applications would be permitted (such as Dolphin or PPSSPP), or if the new rule was limited to officially-licensed retro game collections. Either way, it’s a notable shift for Apple, as any form of emulation has generally been banned from iPhone and iPads.

The first emulator application to be approved under the new rules was “iGBA,” an emulator for the Nintendo Game Boy, Game Boy Color, and Game Boy Advance. It was able to load game ROMs downloaded from the web, and generally worked well from user reports. However, the app appeared to be a slightly-modified version of the open-source GBA4iOS emulator, which was originally created for jailbroken iPhones and later published on the AltStore. The main change in iGBA compared to GBA4iOS was the name change and addition of advertisements.

Riley Testut, one of the original developers of GBA4iOS and creator of the spiritual successor Delta, said on Threads that iGBA was a “knock-off” created without his knowledge or permission. However, GBA4iOS is an open-source project that was never published to the App Store—for people unable to install workarounds like AltStore, it was the only option.

Testut encouraged people to report the iGBA app and leave negative reviews explaining the app’s origins. The emulator was open source under the GPLv2 license, which allows people to create derivatives if proper credit is given, but it’s not clear if iGBA ever did that. Testut also added a clause yesterday stating that explicit written permission is required if the code is submitted to the App Store, after iGBA had already been submitted.

Apple removed iGBA from the App Store only a few days after it was initially approved. The company told MacRumors that the app was removed for violating app review guidelines related to spam and copyright, without clarifying what exactly it violated. The screenshots in the App Store showed off a Pokémon game, which might have been the copyright violation—most emulators on the Google Play Store on Android don’t show games or use homebrew software as demonstrations.

Testut says the developer of iGBA “reached out to me via email to personally apologize for the mess.” However, there’s still seemingly no plan for iGBA or Delta to be published on the Apple App Store as an alternative. The newer Delta emulator is available on the AltStore, which will be an alternative app marketplace in the European Union, but in other regions it requires a complicated sideloading process.

Apple later told MacRumors in another statement that game emulators are allowed on the App Store, but only for “retro” consoles. It’s not clear what consoles Apple considers “retro,” or if there are other limitations.