The regulars of jailbreak will be the most affected by this measure.
Soon following the release of a new update, Apple allows its iPhone users to revert to the previous version of the OS in case of problems with the new update, such as bugs or significantly reduced autonomy. Others take advantage of downgrade for jailbreak their iPhone and therefore benefit from blocked features and applications.
A few days ago, Apple rolled out iOS 15.4, bringing new features such as the use of Face ID with a mask, Universal Control, new emojis and Tap to Pay, the option that turns your iPhone into a payment terminal. . An update that succeeded version 15.3.1 of iOS, providing additional security for WebKit (the Safari engine) and terminals using Braille, which did not always respond correctly.
iOS 15.4 has barely been deployed on all iPhones that Apple is already no longer signing iOS 15.3.1. In other words, it was removed by Apple. It is therefore impossible for those unhappy with iOS 15.4 to return to the previous version, available since mid-February. The jailbreakersthey might go back to iOS 15.3.1 to hack their iPhone.
Besides iOS 15.3.1, Apple also stopped signing tvOS 15.3, which might also have been used for jailbreak.
