If you have installed Firefox via your OS' package manager then updates are performed via your OS' package updating system instead of Mozilla's. If Firefox was pre-installed with your Linux distribution this is probably the case. Unfortunately, if you're using an older version of your distribution you'll probably only have the older major version of Firefox that was available when it was first released. The last update to Firefox 3.0 was 3.0.19 and is probably available via your OS' update mechanism (check your system settings). The most recent version of Firefox 3.x is 3.6.23 and the latest version is Firefox 7.0. It is highly recommended that you use at least latest Firefox 3.6.x so you will have all the security and stability fixes available.

If you were to install or update to the most recent version of your Linux distribution it would have a newer Firefox version in its package manager.

You can of course just download a newer version of Firefox from Mozilla.com instead. https://support.mozilla.com/kb/Installing+Firefox+on+Linux

Hello, I have firefox 3.0.15 installed and it works fine. However under 'About Mozilla' the 'check for updates tab iis grayed out'. In firefox preferences-advanced the update tab for firefox is grayed out. How can I get these items to be selected? I have fedora 10. Thanks, Larry

If you're using the version of Firefox installed by your Linux distribution then you will be updating Firefox via your OS' package update system instead of Mozilla's update system, and thus the update checking built into Firefox will be disabled. If your distro does not provide newer versions of Firefox, you can always install from Mozilla.com yourself. -> Install Firefox on Linux

Make sure that you meet the system requirements for the current Firefox version.

• http://www.mozilla.com/firefox/7.0/system-requirements/
• http://www.mozilla.com/firefox/3.6/system-requirements/

• http://kb.mozillazine.org/Installing_Firefox#Linux