Solved: How do I stop or disable macOS Big Sur software update notification?

Question

How to disable warning about MacOS version update? I’d like to know how to tell the system to be silent about a potential update to Big Sur as it will just annoy. Is that straightforward to do and if so, how? Obviously, I need the system to get security updates where necessary.

Solution 1: Change Software Update settings in System Preferences

Step 1: Open the System Preferences on your Mac.

Step 2: Click on the Software Update.

Step 3: Click the checkbox next to the Automatically keep my Mac up to date option.

Step 4: Click on the Advanced button.

Step 5: Click the checkboxes next to the Check for updates option and Install system data files and security updates option.

Solution 2: Execute Terminal command

Requirements

• Apple School Manager
• Apple Business Manager
• User-approved MDM (Mac Device Management Profile)

Major new releases of macOS can be hidden when using the softwareupdate(8) command with the --ignore flag, if the Mac is enrolled in Apple School Manager, Apple Business Manager, or a user-approved MDM. This change also affects macOS Mojave and macOS High Sierra after installing Security Update 2020-004.

Reference

What’s new in the updates for macOS Catalina

Step 1: Open the Terminal app on your Mac.

Step 2: Type the following in the Terminal window:
sudo /usr/sbin/softwareupdate --ignore“macOS Big Sur” or
softwareupdate --ignore “macOS Big Sur”

Step 3: Press the Enter key.

Step 4: Enter your login password.

Step 5: Press the Enter key.