https://arstechnica.com/gadgets/2022/04/apparent-software-signing-issue-breaks-updates-for-some-studio-displays/

One thing that makes Apple's Studio Display monitor unique—aside from the native 5K display resolution—is that there's basically an iPad inside of it. The monitor includes an Apple A13 chip and 64GB of storage to power some of its smart features, and like any of Apple's other iDevices, it can receive iOS-based firmware updates to add new features and fix bugs.

But also like Apple's other iDevices, this means that you'll sometimes run into problems installing the latest updates for your Studio Display. That was the case over the weekend for some users of the new Studio Displays from Apple who found that they couldn't update the factory firmware (version 15.3) to the latest version (15.4).