CNET

Tackling OS version mismatches when updating

While this usually is not a problem, some people may find installers claiming they do not have the proper version of OS X installed, when in fact they are fully updated with the proper version ...
CNET

Expect OS X to remain up-to-date in the Mac App Store

Apple's OS releases have only periodically been updated on physical media, but with the Mac App Store, expect the available OS version to be maintained at its latest release. Topher Kessler MacFixIt ...
Lifehacker

How to Revisit Every Version of Mac OS X From Your Browser

Brendan is a freelance writer and content creator from Portland, OR. He covers tech and gaming for Lifehacker, and has also written for Digital Trends, EGM, Business Insider, IGN, and more. The Aqua ...
Ars Technica

Running multiple versions of MacOS on the same machine?

Will Parallels or VMWare allow you to install MacOS into the VM? I'm looking to have OS 10.5, 10.4, and 10.3 all running on a Mac Mini, so when users with older versions call, we can follow along with ...