Apple has released updates for many systems. The usual key commonality is security. Especially for older systems like macOS 11 there is a whole range of patches.
The changes that are really noticeable for the user are limited with iOS and iPadOS: you can now limit the downloaded episodes in the podcast app. In addition, presence detection is said to have been improved for HomeKit.
Anyone who installs macOS 12.4 and has an Apple Studio Display can now import firmware 15.5 for the monitor. It stays black for a few minutes, so don’t panic. The webcam quality is said to have improved again. However, the change is marginal. The quality is still significantly worse than the webcam quality of an iMac. This machine can use the entire sensor chip for the image, while with the studio display only a section of the sensor is used due to the center stage function: this reduces the image quality. We assume that the image in the studio display has now reached its maximum and unfortunately falls short of the iMac’s sharp webcam image.