Vá para a documentação do Ubuntu na página FirefoxNewVersion .
When a new version of Firefox comes out, there is some delay until it can be downloaded and run. This page will explain how to install Firefox as soon as possible.
Siga as Instruções para os impacientes que fornecem instruções de instalação do Jaunty e do Karmic para o firefox 3.5 .
Low difficulty, high safety: these packages are maintained and fully tested by the Ubuntu Project