wget http://download-location
sudo tar xjvf thunderbird-24.2.0.tar.bz2 -C /opt
ln -s /opt/thunderbird/thunderbird /usr/bin/thunderbird
[sudo] password for one:
ln: creating symbolic link `/usr/bin/thunderbird': File exists
sudo rm /usr/bin/thunderbird
ln -s /opt/thunderbird/thunderbird /usr/bin/thunderbird
The above is how Idid it, if you don't do it properly you'll find that you are still using the old version (........