iOS 14.4 delivers multiple changes relating to the camera.
The Camera app is now able to recognise smaller QR codes, there's a fix for the image artefacts that could appear in HDR shots taken with an iPhone 12 Pro, and a warning is displayed "when the camera on your iPhone is unable to be verified as a new, genuine Apple camera in iPhone 12, iPhone 12 mini, iPhone 12 Pro and iPhone 12 Pro Max".
Other fixes cover the display of Activity data in the Fitness widget, keyboard issues, Audio stories from the News app in CarPlay not resuming after being paused for spoken directions or Siri, and an issue that could prevent phone calls from being answered from the lock screen if the Switch Control in Accessibility was enabled.
A new feature in Bluetooth support allows users to identify what type of audio device is connected – speaker, car stereo, headphones, hearing aid – "for correct identification of headphones for audio notifications".
When used with a HomePod mini running the 14.4 software, iOS 14.4 on iPhone 11 and iPhone 12 uses the U1 UWB chip to improve audio handoff between the mobile device and the smart speaker, employing visual, audible and haptic effects, and without having to unlock the phone.
iPadOS 14.4 delivers the Camera QR code, keyboard, and Bluetooth audio changes found in iOS 14.4.
The updates include security fixes, and indeed there's no indication that tvOS 14.4 is anything other than a security update.
iOS 14.4 and iPadOS 14.4 include fixes for Kernel (privilege escalation) and WebKit (arbitrary code execution) vulnerabilities that may have been actively exploited.
The Kernel issue has also been addressed in tvOS 14.4 and watchOS 7.3.
In related news, Apple has updated its Xcode development system to version 12.4, which addresses a path handling issue that meant "A malicious application may be able to access arbitrary files on the host device while running an app that uses on-demand resources with Xcode".