Application update procedure question

[Avner Moshkovitz]

I have Fedora core 4 installed.
I want to update Gnome to the latest version (2.6)
I used yum and yum extender, but the available Gnome version for update is
older 2.6
Same thing happened to me with Thunderbird.

My question:
What is the correct procedure for installing new applications and for
updating existing applications?
Should I only use the yum / yumExtender or is there another way to download
the package and install it to the system?

Thanks,
Avner