What just happened? Apple has told an App Store developer that he must remove the functionality of his app or face ejection from the iOS marketplace. The app in question is called "iDOS 2." It is an emulator made to run old DOS games on iPhones and iPads.

Developer Chaoji Li says that he received a letter from Apple telling him that his app, iDOS 2, violates App Store Guideline 2.5.2, which forbids software from installing or launching "executable code" on iOS devices. Li's app has been available on the App Store for nearly seven years, and the notice only came after his most recent update. So somehow, Apple's review board has flip-flopped on its decision to allow it.

"Your app executes iDOS package and image files and allows iTunes File Sharing and Files support for importing games. Executing code can introduce or changes features or functionality of the app and allows for downloading of content without licensing," the takedown notice reads.

Apple had previously restricted Li from bundling games with his app. So he updated it to leverage the document-sharing functionality built into iOS to allow users to import files to run in iDOS 2. His previous app, iDOS, was listed for a short time in 2010 before getting removed.

Li added the import feature in iDOS 2 in September 2020 and has since submitted several other patches without getting a notice. During each re-review, he clarified that his app is not a security threat to Apple's mobile operating system since it operates within a sandbox. It is unclear why the app was flagged this time, but Li says his app has recently gotten a bit of publicity, which may have caused Apple to scrutinize his code more critically.

Apple says Li has two weeks (as of July 22) to remove the ability to execute code from iDOS 2. The developer said that he will not comply with the order because it would render the app useless and thus "betray" customers who have paid for the app. As such, Apple will likely remove the $5 app in less than two weeks.

As we have seen with past removals, apps already purchased and installed on iPad and iPhone will remain functional until Apple makes significant changes to iOS that require developers to update. At that time, anyone with the app installed will get the familiar message, "This app needs to be updated by the developer to work on this version of iOS" when trying to launch iDOS 2. It is also worth mentioning that iDOS 2 is not one of a kind. Power DOS for iOS is more or less the same nut in a different shell.