On Sunday, it was reported that a growing number of Studio Display owners were unable to update their display to iOS 15.4. Apple has since resolved the issue, which was apparently caused by the software not being verified by Apple servers.
MacRumors now reports iOS 15.4, the latest software update for the Studio Display, had been unsigned by Apple as of late last week, making software updates for the display impossible. The issue was exposed to the public by a series of tweets. Apple a few hours later resigned iOS 15.4 for the Studio Display, making software updates for customers once again possible.
Apple stopped signing iOS 15.4 on 4/7
On 4/8, users started reporting that they couldn't update the Studio Display to iOS 15.4 Firmware.
As of one hour ago, iOS 15.4 Firmware for the Studio Display (Appledisplay2,1) is being signed again
The firmware update installing now! 👍 https://t.co/Sn1TyKgLkq pic.twitter.com/pO7rSGox1a
— Mr. Macintosh (@ClassicII_MrMac) April 11, 2022
Apple’s new Studio Display runs iOS 15.4 as its current operating system, although updates to the Studio Display are not coordinated with the traditional iOS and iPadOS releases, as Apple has already released iOS 15.4.1 and iPadOS 15.4.1.