Apple closes the verification channel for iOS 12.5.5 official version
Thanks to CTOnews.com users RTCs for the lead delivery! CTOnews.com September 9 news, Apple stopped signing iOS 12.5.5 firmware, closed the verification channel. iPhone, iPad, and iPod touch software upgrades will no longer downgrade or revert to iOS 12.5.5 via iTunes or Finder.
Last September, Apple pushed iOS 12.5.5 update (build number: 16H62) to iPhone and iPad users, which is applicable to older iPhone and iPad models that cannot run iOS 15. According to Apple's release notes, this is a security update that fixes vulnerabilities in CoreGraphics, WebKit, and XNU.
In early September, Apple released iOS 12.5.6 (build number: 16H71) update for older iPhones and iPads, with security updates and bug fixes for devices that couldn't update to iOS 15. This is Apple's first update to iOS 12 since September 2021.
The following devices cannot be upgraded to iOS 15 and iPadOS 15 and later:
iPhone 5s
iPhone 6
iPhone 6 Plus
iPod touch 6
The original iPad Air
iPad mini 2
iPad mini 3