Ubuntu: How to install an old Firefox version

If you want to install an old version of Firefox, you just have to follow these steps:

In this case, I had Firefox 4.5.0 and now I want to install Firefox 47.0.1


First, open your terminal

1. Download firefox 47.0.1
   
   wget https://ftp.mozilla.org/pub/firefox/releases/47.0.1/linux-x86_64/en-US/firefox-47.0.1.tar.bz2
2. Unzip Firefox
   
   tar -xjvf firefox-47.0.1.tar.bz2
3. We remove the old version
   
   sudo rm -rf /opt/firefox*
4. we move the unzip firefox 47.0.1 to the firefox folder
   
   sudo mv firefox /opt/firefox
5. create symbolic link
   
   sudo ln -sf /opt/firefox/firefox /usr/bin/firefox