Users will no longer be able to downgrade to Apple iOS 13.4 after iOS 13.4.1 update
Bugs, that were fixed with the new update, included an issue when FaceTime-calling an older iPhone device and a small Bluetooth issue, where some users were unable to select Bluetooth from the quick actions menu in Settings. Additionally, there was a problem with the flashlight on the newest iPad Pro that sometimes failed to activate from the Control Center or when the device was locked.
Now, AppleInsider reports that the older iOS 13.4 will no longer be code-signed, meaning that users will not be able to downgrade to it, which includes downloading it as well as installing it on their iPhones. This is a normal practice in Apple as it routinely stops signing older code soon after the release of a new iOS built.
This is done partly to protect users from hackers who would want to take advantage of newly discovered vulnerabilities in older code. Additionally, apart from security, this move assures iPhone users are up-to-date with the latest version of the operating system and they get to have all the new features added with the software.
The previous iOS 13.4 was a major update, allowing people to share folders on iCloud, redesigning the Mail app, delivering new Memoji stickers and additionally, adding cursor support for iPadOS.