Apple has stopped signing iOS 27.0.1. A fresh check of the signing tracker that follows Apple’s servers shows the version is no longer on the signed list, ten days after iOS 27.2 shipped on October 26. The downgrade path back to the version Calif jailbroke on stage in Paris is now closed for everyone who did not save SHSH2 blobs while the window was open.
This is the day the jailbreak series has been counting down to. On October 30 we reported that iOS 27.0.1 was still signed, on day four, and that the window typically lasts 7 to 14 days. It lasted ten. The flip also matters for a second reason: the signing window was the main thing standing between Calif and its promised technical writeup, and that obstacle is now gone.
The November 5 check: 27.0.1 is gone from the signed list
The ONE Jailbreak signing status page, updated on November 5, 2026, now lists three signed versions: iOS 27.3 beta, iOS 27.2, and iOS 26.7.2. iOS 27.0.1 is not among them. Neither is iOS 27.1, the version that shipped on the iPhone Duo, which means the Duo’s launch-day firmware has lost its signed path back as well.
A second source confirms the change. The ipsw.me firmware API, which reads Apple’s signing servers directly, shows iOS 27.0.1 build 24A446 as unsigned, while iOS 27.2 build 24B119 remains signed. The last time we verified the window, on the morning of October 30, 27.0.1 was still signed. So the window closed at some point between October 30 and today. Apple gives no warning when it flips, and it never announces the change, which is why the tracker page simply updates and the older version disappears.
Signing is per device, not global, so the status can vary by model in theory. In practice, when Apple closes a window it closes it across the board, and both the tracker and the ipsw.me data point the same way today. If you are on iOS 27.2, there is no longer any supported route back to 27.0.1.
What closing the window actually takes away
Every iPhone restore needs Apple’s live signature for the exact firmware being installed. While a version is signed, anyone can download its firmware file and restore or downgrade to it. Once signing stops, that file becomes useless for a fresh install, unless the owner saved an SHSH2 blob for that version on that exact phone while it was still signed.
That is why we urged readers to save their blobs on October 29, on day three of the window. A blob is a small file that captures Apple’s signature for one firmware on one device. It costs nothing to save and it cannot be created after the window closes. From today, nobody can save a new blob for iOS 27.0.1, and anyone who did not save one has lost the downgrade option permanently.
Even a saved blob is not a guarantee. Restoring unsigned firmware with a tool like futurerestore also needs the Secure Enclave and baseband parts of the currently signed version to be compatible, and community reports have found futurerestore unreliable on modern devices. A backup made on iOS 27.2 cannot be restored onto 27.0.1 either, because Apple does not allow a newer backup onto an older version. The practical result is simple: for almost everyone, iOS 27.0.1 is now history.
Why this changes the writeup watch
Calif has said from the start that the full writeup of the Paris chain will come in due time, and that the team is disclosing the vulnerabilities to Apple rather than releasing an end-user tool. The reason for the wait was never mysterious. Publishing the bug chain while iOS 27.0.1 was still signed would have handed anyone a working jailbreak on a version they could still install. ONE Jailbreak put it plainly in its report on the iOS 27.2 fixes: it hoped Calif would release a writeup once 27.0.1 stops being signed.
That condition is now met. It does not mean a writeup is coming tomorrow, or at all. Calif has posted nothing since the November 3 video, and the team has given no date. But the main argument for holding the details back has expired along with the signing window, and the next Calif post is now the thing to watch.
The November 3 video is the other half of the context. Calif showed an iPhone 18 Pro jailbroken under Lockdown Mode, with the jailbreak surviving an update to iOS 27.2. Apple had not commented publicly on that video as of November 4. Calif researcher Stefan Esser has said most of the flaws behind the Paris demo are already fixed in iOS 27.2, which is the version everyone should be running now.
What to do now
If you are still on iOS 27.0.1, the decision the signing window forced is now made for you. There is no longer a signed path back, and staying behind means staying on a version with more than 160 documented flaws that Apple patched in iOS 27.2, including over 30 WebKit fixes and about 15 kernel fixes that India’s CERT-In rated high severity on October 28. Update to iOS 27.2 through Settings, General, Software Update.
One group is not covered by that advice: anyone whose iPhone is still on iOS 26 or earlier and has not yet crossed into iOS 27. Signing is not the only door. The delayed OTA channel Apple built for managed devices can still offer 27.0.1 to those phones, and its window runs until January 24, 2027. Our step-by-step walkthrough covers who qualifies and how it works: how to upgrade to iOS 27.0.1 with DelayOTA from iOS 26 or earlier.
If you saved SHSH2 blobs for 27.0.1, keep them somewhere safe. They are the only remaining route back, and they may matter if Calif ever publishes a proof of concept. If you did not save them, there is nothing to do about it now, and nobody selling a blob, a downgrade service, or a jailbreak download can change that. No public jailbreak tool exists for any iOS 27 version, and Calif has said it has no plans for an end-user tool.
The other updates in flight do not change this picture. iOS 27.2.1 is still in internal testing as of November 4, with no public build seeded, and the first iOS 27.3 developer beta arrived on November 3 for a public release in December. Neither has any connection to the jailbreak chain that has been confirmed.
So the scorecard, ten days after iOS 27.2 shipped: the signing window is closed, the downgrade era for this chain is over, and the ball is now entirely in Calif’s court. The team has three demonstrations behind it, an untethered jailbreak, a Duo jailbreak, and a Lockdown Mode jailbreak that survives an update, and zero published bug chains. The next development in this story, if there is one, will be a Calif post, not an Apple signing change, because there is nothing left to sign.
