April 03, 2013, 3:43 PM — Here's how you can install Firefox 20 to your Ubuntu 13.04 system.
1. Open a terminal window.
2. Type in the following commands then hit Enter after each.
sudo add-apt-repository ppa:mozillateam/firefox-next
sudo apt-get update
sudo apt-get install firefox
For more, see the original article at the link below.