Install modern browser on MacOs 10.4.11

Solution 1:

Autoupdate will only update the current system (e.g. 10.4.0 -> 10.4.11), not upgrade it (e.g. 10.4.x -> 10.5.x). Whether you can upgrade depends on the hardware model; you can look it up at everymac.com (look for the "Maximum MacOS" statistic).

If you can run a newer version of Mac OS X, getting an installer disc may be tricky. For example, if you can run 10.5 Leopard, archive.org has several Leopard Install DVD images. 9A343 is a beta-test build, so you don't want that, but there seem to be two drop-in DVD images (part #2Z691-6040-A) which IIRC is what Apple "dropped into" computers that had been manufactured but not sold when 10.5 came out, so it should work. You'll need to burn it to a DVD-R, then boot from that to do the installation. Then download & install the 10.5.8 combo update and then security update 2012-003.

As for a browser: if you have a PPC Mac, you could run TenFourFox (although development is in the process of ending).