Apple has discontinued the signing of iOS 18.3.1. This decision effectively blocks iPhone users who have upgraded to iOS 18.3.2 from reverting to the prior software iteration, iOS 18.3.1. The current operating system, iOS 18.3.2, was released on March 10th.
The act of ceasing to sign older iOS versions, such as iOS 18.3.1, is a routine procedure implemented by Apple after the release of new software updates. This practice is crucial for maintaining the integrity and security of the iOS ecosystem.
Unsigned software like iOS 18.3.1 cannot be installed on an iPhone due to a server-side verification process, ensuring that users are restricted to installing only the latest, authorized versions of the operating system. At this time, iPhone models compatible with iOS 18 are limited to downloading and operating iOS 18.3.2.
The restriction placed on installing older iOS versions, including iOS 18.3.1, and the prohibition of downgrading, is designed to ensure that devices operate with the most recent security enhancements and bug fixes. By maintaining a uniform and current operating system across its devices, Apple minimizes vulnerabilities and provides a more consistent user experience.
This practice is a fundamental aspect of Apple’s software management strategy, designed to protect users and maintain the overall stability of the iOS platform.
More here.