Google has announced plans to drop support for Mac OS X 10.5 in Chrome. If you’re a Mac user, the search giant is recommending that you either upgrade your Mac to 10.6 (Snow Leopard) or 10.7 (Lion).

The change will take effect when Google Chrome 22 is released (which can happen as soon as today and as late as next week). The latest stable version of Chrome is 21, and that’s the last one Mac OS X 10.5 will be able to use.

Here’s the full message from Google:

Google Chrome on Mac OS X 10.5 (Leopard) will stop receiving any updates following Chrome 21. This includes new features, security fixes and stability updates. If you’re not sure what OS version you’re on, go to the Apple icon on the top left corner and click About This Mac to find out. If you already have Chrome installed, you can still use Chrome, but it will no longer be auto-updated. In addition, you’ll be unable to install Chrome on any Mac still running 10.5 (which is an OS X version also no longer being updated by Apple). While we understand this is an inconvenience, we are making this change to ensure we can continue to deliver a safe, secure, and stable Chrome for the most Mac users possible.

Mac OS X Leopard was released on October 26, 2007, meaning next month it will be five years old. The latest version of the Mac operating system is OS X 10.8.2, which was released this week, but it’s not available for all Macs.

It’s not too surprising that Google has made this move. The latest numbers from Net Applications show Leopard has only 0.70 percent market share. That’s just a tenth of Mac’s total market share last month: 7.13 percent.

See also: Google launches Chrome Time Machine on the browser’s fourth birthday and Google kills Internet Explorer 8 support in Google Apps

(Hat tip Hacker News)

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