Just to expand on previous answers, here is how to remotely do the same as the accepted answer, using a passwordless upgrade over ssh that will get your box upgraded to the latest version. It is copied off my own blog entry.
All of these steps assume your package repository is working. Meaning if you execute apt-get update you are not presented with lots of 404s due to having an outdated version. You need to fix that first, so see this answer for that.
0. Update all existing packages
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade
1. Set up passwordless execution
Add your self to the list of users that can execute do-release-upgrade using sudo without entering a password is achieved by executing
sudo visudo -f /etc/sudoers.d/do-release-upgrade.
and adding the following line, substituting my-username for your own of course:
my-username ALL=NOPASSWD: /usr/bin/do-release-upgrade
2. Start incremental upgrades
Log out and execute the following command from your computer. It will do an upgrade without prompting you for input (accepting all default answers), wait for the computer to reboot, and then try upgrading again. It runs until you are upgraded to the latest version.
while true; do
ssh my-user@my-server sudo do-release-upgrade -f DistUpgradeViewNonInteractive;
sleep 120;
done
3. Fix configuration files to their previous state
Afterwards you will have to move the backed up config files to their previous location as the upgrade process has put default configurations in their place.
Not satisfied with the default answers?
This guy has a way to pre-prepare answers for each prompt, but the downside is that you must know how many prompts there are …
