The action of reverting an iPhone’s operating system to an earlier version. This process typically involves installing a previously signed iOS firmware file onto the device, effectively replacing the current software with an older iteration. For example, a user experiencing compatibility issues with a newly released iOS version might seek to revert to the previous version where those issues did not exist.
This process can address performance problems, resolve software bugs introduced in newer updates, or regain compatibility with older applications no longer supported on the latest iOS. Historically, it offered a means to jailbreak devices on older, more vulnerable iOS versions, though this is less prevalent now due to increased security measures and fewer jailbreak tools available. However, it is crucial to acknowledge that Apple generally discourages this process and may cease signing older iOS versions, making it impossible to revert.