Yesterday, the Google Chrome team released version 22.0.1201.0 for Mac, Windows, and Linux to the Dev channel, and while there weren't any details given on what features this release might contain, the team did note that it was incompatible with Mac OS X 10.5 — more commonly known as Leopard. This OS was released way back in October of 2007, so we can't say we're surprised to hear that Chrome will require a slightly more modern OS going forward. Chrome 20 is the current stable release, so we'd expect Leopard users to get one more fully-baked release before compatibility breaks. For those still running 10.5, it might be time to either upgrade your OS — or grab a new Mac that can support newer versions of OS X. The latter course might be the only option for some Leopard users, as it was the last version of OS X to run on the venerable PowerPC hardware.