Apple recently released iOS 18.3.1, and as is traditional, it has now stopped signing iOS 18.3, making downgrading to that version of iOS no longer possible.
The iOS 18.3.1 software can be downloaded on compatible devices over the air by going to “Settings” -> “General” -> “Software Update.”
According to Apple’s release notes, iOS 18.3.1 includes bug fixes and security updates.
According to Apple’s security support document for iOS 18.3.1 and iPadOS 18.3.1, it addresses an accessibility vulnerability that could disable USB Restricted Mode on a locked device.
Exploiting this vulnerability requires physical access to a device, and Apple says that it was used against specific individuals.
Impact: A physical attack may disable USB Restricted Mode on a locked device. Apple is aware of a report that this issue may have been exploited in an extremely sophisticated attack against specific targeted individuals.
The vulnerability was fixed with improved state management, according to Apple.
While falling back to an older iOS version is often used by users who jailbreak their iPhones, it can also be helpful for users who experience significant bugs after upgrading to the latest version of iOS.
By preventing users from downgrading their devices to older versions of iOS, Apple ensures that the devices are kept up to date with the newest security improvements.
