macOS Big Sur, Apple's latest major update for its desktop operating system, will feature faster software updates in the future thanks to background installation.
macOS already supports download software updates in the background, however, installation is a different story. When the update is downloaded, the installation process starts afterward and requires a few reboots to complete. Apple has finally improved this process by enabling updates to install in the background.
Once macOS Big Sur is installed, software updates begin in the background and complete faster than before — so it’s easier than ever to keep your Mac up to date and secure.
Apple did not provide any technical details in any WWDC session for this update, neither did they announce it as one of the features during the virtual keynote. For now, if you download and install macOS Big Sur developer beta, the installation takes a long time. Once Apple releases the next beta this month, we might get an idea of how much of noticeable improvement is there when installing software updates in Big Sur.
Apple has also added a layer of security to system volume so that your Mac is protected against any tampering. The signed system volume also helps your Mac in installing software updates in the background. As per Apple's website:
macOS Big Sur introduces a cryptographically signed system volume that protects against malicious tampering. It also means that your Mac knows the exact layout of your system volume, allowing it to begin software updates in the background while you work.
The first macOS Big Sur public beta is expected to release sometime this month. It is expected that the second developer beta might release as soon as next week.