Apple has stopped signing iOS 15.4.1 following the release of iOS 15.5 just over a week ago.
Since the OS is no longer being signed, you cannot downgrade your iPhone to it if you have already installed iOS 15.5.
Apple stops signing iOS 15.4.1
Apple typically stops signing older builds of iOS once a new version drops. Before iOS 15, the company used to keep the signing window for older iOS builds open for around two weeks. But following iOS 15’s release, it has reduced the timeframe to about a week.
Usually, iPhone users who are into jailbreaking tend to downgrade their device to an older iOS release in hopes of an eventual jailbreak tool being available for it. However, no such tool has been released for any iOS 15 build so far.
With iOS 16 just weeks away from its official unveiling, the chances of an iOS 15 jailbreak tool being released are very slim. Instead, you should upgrade your iPhone to the latest iOS 15 release and enjoy the new features it offers.
This move from Apple won’t affect your iPhone if it is running iOS 15.5 — you can always upgrade to the latest available firmware without any issues.
iOS 15.5 packs several minor new features
iOS 15.5 introduced several new features like the ability to send and request money from your Apple Cash card, Apple Podcasts improvements, and some other bug fixes. Since then, the company has even gone ahead and seeded the first beta of iOS 15.6 to developers and public beta testers.
iOS 15.4.1 was a minor update containing some security patches and bug fixes. It also packed a fix for a battery drain bug that was inadvertently introduced in iOS 15.4. You have little reason to stick to iOS 15.4.1 on your iPhone, especially since the likelihood of a jailbreak tool coming out for it is pretty slim.