Question: In the Software Update preference pane, there are several checkbox options. What do they do?
"Check for updates" How often does this happen?
"Download new updates when available" How often does this happen? Is there a check for minimum bandwidth availability (like there is for iOS, where it only updates some updates when on WiFi)?
"Install macOS updates" When/under what conditions does this happen?
"Install app updates from the App Store" When/under what conditions does this happen?
"Install system data files and security updates" When/under what conditions does this happen?
"Check for updates": Background scan every six hours
"Download new updates when available": If background scan finds updates, they start downloading immediately (as long as the checkbox is enabled.) There is no minimum bandwidth check.
"Install macOS updates": Machine learning algorithm predicts when you'll be least active (individual to each Mac) and run updates then. If logged out, same behavior. If multiple users log into the Mac, then the algorithm tries to figure out least active time and run then.
Note: Machine learning algorithm assumes that at least one user account has logged into the GUI at some point. Don't know what happens if nobody logs into the GUI (for example, on a Mac that only has users logging in via SSH.)
"Install app updates from the App Store" If background scan finds updates, App Store updates download and install immediately.
"Install system data files and security updates" If background scan finds updates, if they're critical the updates will install immediately in the background (silent install.) There will be other security updates where the user will be prompted to install, where the user can choose to delay installation.
Question: What kind of third-party installer packages can be installed by startosinstall as part of a major OS upgrade? For example, in my testing only distribution-style flat packages appear to be supported.
Answer: Distribution-style flat packages are supported. Specifically works with packages built by productbuild.
Question: Is documentation available for automated snapshot taking and rollbacks as part of OS upgrades? If yes, where is it located?
Answer: File a documentation Radar.
Question: Will Apple add the status of the stapling service to their status board?
Answer: Ask at the Security lab.
Question: When you launch startosinstall from another script or app, you cannot capture its progress output. Is there a solution for this?
Answer: File a Radar with specifics on how you want to capture the progress output. It outputs to stdout.