Upgrade to BigSur per Script

[MehdiYawari]

Hello Everyone

My team and I are planning an upgrade to Bigsur. and we want to automate it via script to avoid as much user interaction as possible. But as discussed in Jamf Nation, we can't rely on the "software --fetch-full-installer" command. I have tested this command on my Macs with many different macOS. Sometimes it works and sometimes it doesn't.
Is there a reliable way to perform an automatic upgrade to Bigsur via script? 
On many older macOS we could configure the domain account directly on the mac. Now we don't have a domain account on the Mac, but we connect the local account to the domain via Kerboros (SSO extension).
The idea is to upgrade to Bigsur and disconnect the domain account and create a local account connected to the domain via SSO extension without losing any data.

Thanks and Regards

Mehdi

[mm2270]

Why not use one of the downloads of the full installer you have and package it and push as a cached package to the machines in the background? Once it's on the devices, you can use the script to run the actual upgrade.

[jcaleshire]

To add onto this, you could have the Mac pull the Big Sur install assistant .pkg straight from Apple's software update CDN. The script I built to avoid this exact issue relies on a static download URL for the packaged installer that Apple hosts, downloads it, and places the Mac in a static group upon a successful download and checksum verification. The policy to start the update is then scoped to that static group so that once the download is complete, the user can launch the install whenever they like.

[beeboo]

are there any specific flags to run to prevent disruption or notifications to user aside from maybe jamfhelper to let them know its going on?