iOS / iPadOS 14.8 is no longer signed. Downgrading from 15 is no longer possible.

[klasma]

I just updated an iPad (12.9" 3rd gen) from 13.2 to 14.7 (and then to 14.8) using iMazing on Windows with the MDM deferred update method (aka OTA delay), following the procedure in https://pastebin.com/4h5HHcEY. Because I didn't read step 18 right (upgrading iPadOS from Settings), I tried at first to install an IPSW of 14.8, which failed with error code 3194 ("Failed to copy preflight options during recovery mode restore"), both with iMazing and 3utools. Same with the IPSW of 14.7.1. Finally I noticed that Settings > General > Software Update was proposing 14.7, which I then selected and which worked. (I didn't try an IPSW of "plain" 14.7.) After restoring my previous backup, I then upgraded to 14.8 which Settings was now proposing.

I have no idea why Settings with the delay profile proposed 14.7 instead of 14.8. I'm also a bit suprised that it worked, because according to https://support.apple.com/guide/mdm/managing-software-updates-mdm02df57e2a/1/web#mdmfb8077b62 the 90-day deferral period for 14.7 already ended on 10/19. Coincidentally, the period for 14.7.1 supposedly ends this weekend (10/24). 14.8. isn't listed. It's therefore not clear to me when the procedure will actually stop working.

Thanks @Daytona 360 for bringing up the method.

 

[klasma]

I just updated an iPad (12.9" 3rd gen) from 13.2 to 14.7 (and then to 14.8) [...]

As a follow-up, today I successfully updated an iPad mini 4 from 13.6.1 to 14.8.1 using the same general method. (It's an iPad that I had planned to sell but now decided to keep after all.)

At first I was only able to update to 14.8 — 14.8.1 wasn't proposed in Settings. After some pondering, I figured that maybe it's because of the 90-day deferral profile, as 90 days haven't passed yet since the release of 14.8.1 (that would be on January 24). Googling a bit, I found that iMazing provides a free profile editor for Windows (https://imazing.com/profile-editor), so I used that to create a profile with 60 days instead of 90 days deferral (cf. screenshot below). After installing that profile on the supervised iPad, 14.8.1 became available for installation in the Settings app, and the update installed successfully.

I'm not sure how long that process will still be possible. Maybe until 90 days after the choice between 14.8.1 and 15 disappeared from unsupervised devices, which I think was with the 15.2 release on December 13 (so plus 90 days would be March 13). That's just a guess, however, I'm not really clear on the overall logic. Anyway, I'm glad that I was still able to update to 14.8.1 now despite 15.0 having been released already more than 90 days ago.

For reference, here are the restrictions I set in iMazing Profile Editor:

 

[driveparty]

What about upgrading devices from earlier versions of iOS 14? I just got an iPhone 8 with iOS 14.3 today, but I’m not allowed to upgrade it to 14.8?

Wel, you actually still can. There's OTA delay method, google for it of just read here https://www.reddit.com/r/jailbreak/comments/nss3k9