https://wccftech.com/you-can-no-longer-downgrade-to-ios-14-4-1-from-ios-14-4-2-what-jailbreak-users-should-know/

Last month, Apple saw fit to release iOS 14.4.2 to the general public. Now, the company has stopped signing its predecessor firmware build like it always does. Apple has stopped signing iOS 14.4.1 which means that you can no longer downgrade from iOS 14.4.2. The company wants your device to rest on the latest software update and enjoy all the security and stability updates. While the average user might not pique interest in downgrading, the option is considered viable for users looking to jailbreak their iPhones or iPad. Since Apple is no longer signing iOS 14.4.1, here is everything you need to know related to jailbreak.

As mentioned earlier, Apple took away the ability to downgrade to iOS 14.4.1 from iOS 14.4.2. The latter is a second major update that fixed the WebKit vulnerability. Apple patched the vulnerability on all platforms which include macOS 11.2.4, and watchOS 7.3.3. While we are glad that the vulnerability is patched, the impact of the update is worth questioning with respect to iOS 14.4 jailbreak. Since users interested in a jailbreak are most concerned about the update, it is worth noting that Apple's move has no impact on all jailbreak-related operations.