I've never looked into this. What's your method of disabling the Yosemite update notification for 10.7+?

We've run terminal command:

softwareupdate --schedule off

to stop the notifications.

On my 10.8+ computers, I totally disable Notification Center from loading at startup by deleting the file /System/Library/LaunchAgents/com.apple.notificationcenterui.plist. It hasn't caused any issues on the computers and most of my users wouldn't know how to deal with notifications anyways.

Notification Center made it debut on 10.8, not 10.7.

Wow, thanks mm2270! Just realized that mistake!

Thank you hkabik. I might do that on my 10.6 and 10.7 computers. They are already so outdated that updates do matter much anyways.

We manage our software update scheduling manually via Casper so it behooves us to have the internal schedule disabled even on modern OS machines. But it definitely seems like a safe option for legacy OS's that aren't likely to have much coming to them in the future.

If you type in terminal: man softwareupdate it'll give you the list of commands for software updates - one being --ignore.

Once you have the identifier for Yosemite (softwareupdate -l will give you the full list of available) you can:

softwareupdate --ignore *identifier*

Thank you jonnydford, this also is a good answer. I will look into it more.

jonnydford's method won't work because the Yosemite installer isn't being offered by software updates, it's being offered by the Mac App Store.

I realized that when trying it today. It is good for any other software updates but not new OS's.