If you don’t want to leave Software Update to install updates automatically, here are the options for using softwareupdate, SilentKnight and silnite instead.
softwareupdate
You might want an old macOS or OS X installer to build a Virtual Machine, or for an old Mac. Here’s how to get them, and old versions of Xcode.
For those who want macOS updates promptly, SilentKnight can be a help. But don’t use it to download and install an update.
What to do when SilentKnight offers you large macOS updates, or updates which you don’t want to install just yet, and other problems.
Full macOS installers come in different presentations according to how they’re obtained. Explained here are what’s in an installer app, and how a bootable installer disk works.
In macOS 11.5.1, Apple has squeezed a thimbleful of a patch into a ten-gallon can of update, more than 99% of which is overhead.
Details of how the Content Caching server handles a cache macOS security data update, and both client and server handle an App Store update.
Using Activity Monitor and command tools to assess performance of a content caching server, and diagnosing problems from the log.
Although updating each M1 Mac requires 1 GB of direct download from Apple, there are great economies in running your own Content Caching Server. And why Apple doesn’t want to offer standalone Big Sur updates.
Not only has Apple not provided standalone updaters for macOS 11.2, or for Mojave and Catalina Security Updates 2021-001, but it has removed the Big Sur 11.1 installer. It’s just like iOS now.
The Eclectic Light Company 