Sorry! While we'd like Firefox to be available on as many computers as possible, we have limited resources. Mac OS X 10.4 is no longer eligible for security updates from Apple, and other products that Firefox works with (like Flash) are also no longer updated on 10.4.

Supporting PowerPC Macs is especially resource-consuming, because Firefox contains JavaScript compilers that would need extra work just to run on these machines. Supporting OS X 10.4 in our main code base was also making it more complicated and difficult to take advantage of features in newer version of OS X.

However, there is an unofficial version of Firefox 4 that does run on PowerPC-based Macs with OS X 10.4. You can download it at http://www.floodgap.com/software/tenfourfox/

And you can still download the official Firefox 3.6 release for 10.4, and it is still a supported release (still receives security updates from Mozilla): http://www.firefox.com/all-older.html

Thanks for the reply to this question. I would certainly like to at least see security updates for 3.6 for PowerPC Macs be continued for a long while. I noticed that TenFourFox claimed it had sent you data about its powerpc code, so it would be nice if there were an official release for PPC eventually...any chance of that? TenFourFox still has its issues, so I'm not sure I want to use it for, say, banking. However: Can I ask if Mozilla basically recommends it? Is TenFourFox a secure browser? I always worry about unofficial builds for this reason.

Old Firefox releases are supported for at least 6 months after the release of the new version, and usually much longer. For example, Firefox 3.0 was supported until March 30, 2010 (nearly a year after Firefox 3.5 was released), and Firefox 3.5 is still supported today (more than a year after Firefox 3.6 was released).

Thanks for the reply.

So...thanks mbrubeck. But is it better to use the officially supported 3.6, or TenFourFox? Can you speak to their relative usability/safety/stability/Javascript compatibility, and so on?

Time to remove Firefox from all of my company's computers. It is not acceptable to have different browsers across platforms.

jimmeans, if your company still has computers running Mac OS X 10.4 (especially PowerPC Macs) then you are no longer receiving security fixes for your operating system or browser plugins, and your data is in danger. Other major browsers like Safari are also no longer updated for Mac OS X 10.4 either -- so if you remove Firefox then you might not have any other browser to turn to. (At least Firefox 3.6 still receives security updates on these machines, while the OS and other software does not.) You should probably investigate updating your OS and/or hardware.

marivaux: Sorry, I am not familiar enough with TenFourFox to speak to the quality of their code. Most of the code is the same code as official Firefox 4 releases, and it should benefit from the many improvements that have gone into Firefox 4. Their team is working together with Mozilla, and we are happy to see their work. But if you want the highest guarantee of support and security from Mozilla, you should stick with the official Firefox 3.6 release.

Thanks, MBrubeck. I appreciate the candid and informative response! I should say that 10.5.8 still receives security updates (and even new versions of Itunes and Safari) from Apple, even on PowerPC--that's the OS I am using. I'm guessing that some of the people reading this thread are 10.5.8 users, despite the thread title. That's why I'm happy to see that FX 3.6 is still receiving security updates--10.5.8 on PowerPC is still a very usable and (I think) secure system (well, aside from Flash).