upgrade firefox on ubuntu

solution 1.

sudo add-apt-repository ppa:ubuntu-mozilla-security/ppa
(sudo add-apt-repository ppa:mozillateam/firefox-next ??)

sudo apt-get update

sudo apt-get install firefox

solution 2.

Download firefox.tar.gz2
www.mozilla.com/firefox/

Extract it
tar xvjf firefox-59.0.tar.bz2


Move to /opt
Remove previous one if you have
sudo rm -rf /opt/firefox

Move the downloaded firefox directory to /opt
sudo mv firefox /opt/firefox_xx


Set up symbolic links
sudo mv /usr/bin/firefox /usr/bin/firefox-old
sudo ln -s /opt/firefox_xx/firefox /usr/bin/firefox