Under Ubuntu, installed packages can be updated to their newest version via
apt-get, following the same process as if you were initially installing

To update a package, first, make sure that the package index on the server
is up to date by running:

sudo apt-get update

Next, the package itself can be upgraded to the newest version with the
following command, replacing PACKAGE with the name of the package:

sudo apt-get install PACKAGE

If the installed package is already the newest version available, the
apt-get command will state that in its output.

The full usage of the apt-get command can be viewed at: