The newest officially supported system is often not the ideal one to use. But is it a wise idea? Not always, in my estimation. It seems that a lot of people with older Macs are interested in installing OS 9.2.2, and again, there is an installer hack available ( OS 9 Helper) that help them to do so. On the Classic Mac OS side, there is Mac OS 9.2.2, which only officially supports the same machines that OS X does. If you’re really determined, you can probably get OS X to install on a Kanga using Ryan Rempel’s XPostFacto installer hack for some unsupported Macs, but is it worth the trouble on a Mac limited to 160 MB of RAM? I’m doubtful. For example, PowerBooks prior to the G3 Series WallStreet, which was introduced in May 1998, are not supported by OS X, which means that the original 250 MHz PowerBook G3 (3500/Kanga) has the dubious distinction of being the only G3 model Apple ever made that isn’t supported by OS X. The appropriate system to use depends on variables like the speed of your machine, how much RAM you have, what you use the computer for, and how much performance (speed again) you’re willing to trade off in order to have the latest bells and whistles. There is no all-purpose boilerplate answer. Questions I get asked fairly frequently are variations on the general theme of upgrading the operating systems of older Macs to more recent system versions.