Apple released iOS & iPadOS 15.4.1 last week with a fix for the battery drain issue that had been widely reported by a myriad of users on iOS & iPadOS 15.4 and to address some security holes that needed patching.
One week later, Apple has now closed the signing window for the older iOS & iPadOS 15.4 firmware, a move by the Cupertino-based tech company that prevents most ordinary forced upgrades or downgrades to this version except for why way of DelayOTA or futurerestore.
Apple ritualistically unsigns older firmware, so this should come as no surprise to anyone. In fact, it helps Apple by boosting new firmware adoption and pleasing shareholders while ensuring that users are taking advantage of the latest features and patches.
No jailbreak tool currently supports iOS or iPadOS 15.4, so the news doesn’t really impact the jailbreak community much. Work is currently underway by the Odyssey Team for a jailbreak that supports iOS & iPadOS 15.0-15.1.1, while a future update to checkra1n may support all versions of iOS & iPadOS 15 at some point.
Of course, firmware downgrades aren’t only practiced by jailbreakers; new firmware upgrades can sometimes introduce bugs, causing some users to downgrade just to fix their devices in the event of such a bug.
If you’re ever curious what version(s) of iOS or iPadOS are signed for your device(s), then you can visit the handy ipsw.me website to find out. You can also download firmware files directly from our downloads page.