Firefox 3.6 should work fine on a PPC Mac OSX 10.5.8, but Firefox 4.0beta needs an Intel Mac.

For older Macs that aren't supported in Firefox 4.0, try TenFourFox for PowerPC's running Mac 10.4.11 & 10.5.8 .
http://www.floodgap.com/software/tenfourfox/

Sure I have the 3.6 version and use it without any problems.

The download site says only OSX 10.5 is required for the Beta version. Nothing about Intel proc.

Will the sharp version support the PPC architecture?

" sharp version" ?

The Firefox 4.0 (not Beta version)

For older Macs that aren't supported in Firefox 4.0, try TenFourFox for PowerPC's running Mac 10.4.11 & 10.5.8 . http://www.floodgap.com/software/tenfourfox/

Hmm... Download site really says only:

English (US), Mac OS X 10.5 and above

without any mention of the required CPU architecture. As I know, Mozilla site always gives you the correct binary, but here it's not the case: given binary is unusable piece of alien code. Does it make your server-side user-agent analyzing code much smaller?

For Linux, at least I see "x86" on download pages, thus leaving it, and going to upgrade my Iceweasel via apt-get.

Also, thanks for information about TenFourFox. It works great, fast, and stable (despite the beta status). I'm sure official branded builds of Firefox 4.0 may be done too, using code/patches/whatever from TenFourFox guys.

UPD: I made some benchmarking. 4.0b9 is about 3 times faster in JavaScript processing than 3.6.14. So it's obvious that TenfourFox does JIT JS. http://dromaeo.com/?id=128839 (TenfourFox 4.0b9; 10.11runs/s) http://dromaeo.com/?id=128850 (Firefox 3.6.14; 3.19runs/s)

Will the sharp [i.e. final] version support the PPC architecture?

I do have the same question. I see no exact official information about this, only "will probably not" and so on.

Would it be possible to get open source Firefox 4.0 or Mozilla to port to a PowerPC or has the cpu been forsaken altogether?

TenFourFox for PowerPC's is the Open Source solution and it works very good on my iMac G5:s. // Per

OK, I've installed TenFourFox on my G5 iMac. First thing I did was put the Tabs back where they belong. Safari tried putting them on top a year or so ago, but the resulting feedback led them to return them under the Toolbars, at least that is where they are in Safari 5.0.3

If we submit feedback via the option under the Help Menu, is it shared with the developers of the Intel version of Firefox, and vice versa?

Apple made 10.5 deprecate PPC in its lifetime of releases, therefore for 'current' 10.5...no PPC members exist. Fancy that!

Moreover, WebGL (requires a more capable video card, memory/cache footprint over 2GiB, as I expect would Canvas, and other HTML5 objects, even without multiple instances, expectations about OS support of persistent XML pipes) is wholly beyond a G3 iMac. I wonder what shall happen when TenfourFox sees the demos for Firefox 4; flaming X11 NTSC bars? Like W3M on my Amiga 500s, running an antivirus, IDS and firewall on these machines is also prohibitive (see image; though 8 Altivec cores offer some margin.) Bloody waste of power and patience when heating season ends; unless, you run it from your workout or hothouse condenser.

Thanks for recommending TenFourFox, citizen-heroes (TenFourFox devs, et al!) Sed muove, Bruno!

I tried a download of 4.0 several months ago to my iBook G4 laptop OSX-10.5.8, but got "Wrong Architecture" and "Existing Copy Exists" messages. Closing my Firefox Browser allowed the Install to proceed. Then the wrong Architecture Error persisted, and I had to somehow recover my previous Firefox.

Today I got a fresh E-mail from Mozilla extolling the virtues of the latest Firefox 4.0. Figuring the previous problem had been rectified, I naively downloaded it again and re-installed, allowing the Install to blow-away the previous version.

Firefox's excellent auto-updates, had lead me into a false sense of security. It was Deja-vu all over again.

Now I must find and reinstall whatever previous version I was using or try this "TenFourFox" -- beta-version or whatever??? Meanwhile I have a project due.

Hey Mozilla and Firefox are great; but this slip-up is known (here) clumsy and unnecessary. Firefox 4.0 needs better System-Requirements or Warnings somewhere -- even an abort in the Install script.

Thanks for an otherwise great tool.

Downloaded and installed TenFourFox -- couldn't have been easier or quicker. Minor question of ppc 7400 or 7450 (run Terminal.App, ask: "machine"). TenFour looks reputable, aware and on top of the situation. Bonus is that it's optimized for specific hardware. They acknowledge that good (older) running hardware deserves current support. We'll see. --Hal

PS: All my history, favorites and learned patterns are there -- feels right at home, like I never left.

If Mozilla no longer supports the PPC architecture, then the use of the Universal Binary (UB) logo on the all platforms download page is an improper use and needs to be changed to the MacOS logo instead.

http://www.mozilla.com/en-US/firefox/all.html

Your download link should also check for the platform of Mac OS X to prevent people on PPC systems from downloading Firefox 4. It's not really that hard and would certainly prevent problems...including this thread.

For those that don't know, the UB logo (which look very much like a T’ai Chi symbol) identifies the app as an application that can run on both Intel or PPC Mac OS X systems (a.k.a. a fat binary).

Never mind the fact that UB is also loosely used as an identifier for x86 and x86_64 architecture applications since that really hasn't taken off yet and most users don't know that this change has been done to the UB position since Apple dropped PPC.

I went and got my old 3.6.10 Firefox back at oldapps.com and it still has all the old bookmarks and such.

And now I even get a no go panel for the 7-11-update Fx4 G5 8.0 which also says that my architecture OSX 10.5.8 does not support this new version. 7.0 does run although I miss security signs form e.g banksites like a lock-icon.