A change to the App Store rules reverses a very old rule that prohibited emulators on the iPhone and iPad.
One of the App Store's longest standing rules is a prohibition on apps that run external code. This has meant a de facto ban on console and classic game emulators.
A change to guideline 4.7 of the App Store changes all that.
Specifically, Apple is now allowing "software that is not embedded in the binary" to run inside apps hosted in the App Store. The company is specific as to what can run, and "retro game console emulator apps" are included in the list.
Specifically, Apple says that the following provisions must be followed:
Given how existing emulators often rely on user-provided ROM files, it's not clear how this will be enforced. In emulators on jailbroken devices, some rely on Files to import ROM files and BIOS files, and others have a custom file import feature.
Despite what console manufacturers' stance, the concept of emulation is legal. What is not legal is using ROM files that the user does not own, or source code from the manufacturers to make the emulators, which is where the Playstation emulator by Connectix fell down over two decades ago.
There are a series of emulators available now for other platforms — like the Mac. It likely won't take long for these emulators to arrive on iOS and iPadOS.
Source: Appleinsider