How to Upgrade Ubuntu Server to the Next LTS Release

Step 1: Take a backup

Don't skip this step. If the upgrade fails halfway or an application doesn't work with the new release, a backup is the only safe way back:

• Your provider's server backup: Make sure there's an up-to-date server backup right before the upgrade.
• A separate backup of your data: Back up database dumps, website files and the settings under /etc separately.

We cover backup methods in our Server backups guide.

Step 2: Fully update the current system

Before the upgrade, install all updates for the current release and reboot the server:

sudo apt update
sudo apt full-upgrade
sudo apt autoremove
sudo reboot

Once the server is back up, check that everything is working. Having a healthy system before you start means that if something breaks, you know the upgrade is the cause.

Step 3: Preparation checks

• Disk space: The upgrade needs a few GB of free space. Check with df -h.
• Third-party repositories: Note the external repositories you added for Docker, PHP or databases. The upgrade tool disables these repositories; after the upgrade, you need to enable them again for the new release.
• Application compatibility: The new release usually comes with new versions of PHP, Python, Node.js and databases. Make sure your applications work with these versions.
• Access: Check that you can reach your provider's web console; if the SSH connection drops, that's how you get to the server.

Step 4: Start the upgrade

Make sure the upgrade tool only offers LTS releases; the /etc/update-manager/release-upgrades file should contain this line:

Prompt=lts

Start the upgrade in a tmux session to protect it against dropped connections:

tmux new -s upgrade
sudo do-release-upgrade

The tool calculates the packages to upgrade and asks for your confirmation. When it runs over SSH, it also tells you it will start a second SSH service on an extra port as a fallback. If your firewall blocks that port and your main connection drops, you may need to open the port temporarily to use this fallback connection.

Questions you may be asked during the upgrade:

• Modified configuration files: When a new version arrives of a configuration file you edited before (for example sshd_config), you're asked which one you want to use. If you're not sure what you're doing, keep the currently installed version is the safest choice.
• Restarting services: While some libraries are updated, you're asked to allow services to be restarted.
• Removing obsolete packages: At the end of the upgrade, you're offered the option to remove packages that are no longer used.

When it's done, the tool asks you to reboot the server.

Step 5: Post-upgrade checks

Once the server is back up:

lsb_release -a
systemctl --failed

• lsb_release -a should show the new release.
• systemctl --failed lists services that failed to start; the list should be empty.

Then check the following:

• Websites and applications: Open the pages and look at the applications' logs.
• PHP version: If the PHP version changed with the new Ubuntu release, update the PHP-FPM socket path in your Nginx configuration (for example php8.1-fpm.sock → php8.3-fpm.sock) and install the PHP extensions you need for the new version. The details are in our How to change the PHP version guide.
• Third-party repositories: Enable the disabled repositories again with the new release's name and run sudo apt update.
• Firewall and SSH: Check that your settings were kept and that you can open a new SSH connection.

Finally, clean up packages you no longer need:

sudo apt autoremove

Alternative: a clean install and migration

Instead of an in-place upgrade, setting up a clean server with the new release and moving everything over is also a strong option:

• Old settings and packages that have piled up over the years are left behind.
• Because the old server keeps running, there's no downtime during the switch; when the new server is ready, you bring it into service by changing the DNS.
• If something goes wrong, it's easy to go back to the old server.

This method is safer especially for complex, long-running servers. We cover the steps for moving a website to a new server in our How to migrate a website guide. If your application runs with Docker, the move is much simpler; the details are in our How to install Docker guide.

A note for Debian

On Debian, you upgrade by replacing the release name in the repository addresses with the new one and running apt full-upgrade. Debian only supports upgrading to the next major release at a time; don't skip a release, and before upgrading, read the upgrade instructions Debian publishes in the release notes for the new release.

Ubuntu on Nodesty

On Nodesty AMD Ryzen 9 9950X VPS and AMD EPYC 7763 VPS plans, you can choose between different releases of Ubuntu, Debian and AlmaLinux when you order. Your free daily backups kept for 7 days give you a safety net before the upgrade, and if your SSH connection drops, you can reach your server through the web console. If you prefer a clean install, you can reinstall your server with a new release from the panel; reinstalling deletes the data on the disk, so take a backup first.