On Friday local time, Apple submitted an additional brief to the US Ninth Circuit Court of Appeals, challenging a punitive injunction imposed on the App Store that prohibits app developers from directing users to external websites for payment processing. This injunction, a product of a protracted legal battle between Apple and Epic Games, mandates that Apple allow third-party apps to guide users to external payment sites and prohibits Apple from collecting any commissions on these transactions. In its filing, Apple is likely to contend that the injunction poses a substantial threat to its established business model.