Hello, from Firefox menu select Help then About Firefox and a popup will open.

Normally if you do that FIrefox it will start update it self if it's not already up to date.

Otherwise download manually the latest version of Firefox from this link https://www.mozilla.org

Install Firefox on Linux

Make sure that you meet the System Requirements (GTK+ and GLib) for the current Firefox version.

• http://www.mozilla.org/en-US/firefox/24.0/system-requirements/

You can find the full version of the latest Firefox 24.0 release in all languages and for all Operating Systems here:

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