Apple, yet once again, wins the game here in supporting older devices with software updates. Apple had released iOS 12.4.4 on the 10th of December 2019 for devices like the iPhone 5s, iPhone 6, iPhone 6 Plus, iPod Touch (6th generation), iPad Air (1st Generation), iPad Mini 2 and for the iPad Mini 3. A bunch of software updates were pushed to all the supported devices across the globe on the 10th of December, which includes iOS and iPadOS 13.3, macOS Catalina 10.15.2, macOS Mojave 10.14.6, macOS High Sierra 10.13.6, tvOS 13.3, watchOS 6.1.1, watchOS 5.3.4 and of course, iOS 12.4.4. You may notice that Apple has kept into account about the support for older iPhones and Macs. watchOS 5.3.4 was released for watches paired with an iPhone which is supported upto iOS 12. This shows the hard work and effort of Apple. They are trying to support older devices so that they can keep our iPhones speedy and safe & secure.
The build number for iOS 12.4.4 is 16G140. Apple has mentioned in their release notes, about a FaceTime bug which they fixed in iOS 12.4.4 which may have lead to arbitrary code execution.
Apple may have been trying to patch the checkra1n Jailbreak exploit for these older devices by these software updates. They may have tried to patch the Jailbreak exploit in the earlier versions of iOS 12, like iOS 12.4.2 and iOS 12.4.3. For those who are unaware of the checkra1n Jailbreak, it is a Jailbreak which is enabled through a hardware bootrom exploit known as checkm8 by axi0mX. This is a hardware exploit, which most probably, cannot be fixed by a software update. This will allow jailbreak developers to create an exploit for any software version. The devices from the 4s to the iPhone X. Apple had also released an update for the iPhone 4s and the iPhone 5 which were iOS 9,3,6 and iOS 10.3.4 respectively in which they may have tried to fix the bootrom exploit.
To stay secure, it is highly recommended to update your older devices to iOS 12.4.4 unless you would think of Jailbreaking your iPhone.
