How to Upgrade FunOS 24.04 to FunOS 26.04 LTS

Upgrading your system ensures you get the latest features, improved performance, and long-term support. This guide will walk you step by step through upgrading any version of FunOS 24.04 (including 24.04.1, 24.04.2, 24.04.3, 24.04.4, and 24.04.5) to FunOS 26.04 LTS, which is based on Ubuntu 26.04 LTS.

Pre-Upgrade Checklist

Before starting the upgrade process, make sure you are prepared:

  • Backup your data
    Save important files to an external drive or cloud storage.
  • Connect to a power source
    If you are using a laptop, plug it in to avoid interruptions.
  • Check available disk space
    Make sure you have at least 10 GB of free space. You can check this by opening a terminal and running df -h /.

Step 1: Open a Terminal

You can open the Terminal in several ways:

  • Click Menu → Terminal
  • Click the Terminal icon in the tray
  • Press Ctrl + Alt + T

Step 2: Update Current Packages

Before upgrading, ensure your system is fully up to date.

sudo apt update
sudo apt upgrade
sudo apt full-upgrade

Step 3: Reboot Your System

Restart your system to ensure all updates are properly applied.

sudo reboot now

Or:

  • Click Menu → Log Out → Reboot

Step 4: Run the FunOS 24.04 Update Script

Before proceeding with the upgrade, run the FunOS 24.04 update script to apply any necessary system fixes.

rm -f funos-update
wget https://raw.githubusercontent.com/funos-linux/funos-updates/main/ubuntu/24.04/funos-update
sudo install -m 755 funos-update /usr/bin/funos-update
sudo funos-update
rm -f funos-update
sudo apt autoremove --purge

Step 5: Start the Upgrade Process

Run the following command to begin upgrading:

xscreensaver-command -exit
sudo do-release-upgrade

The xscreensaver-command -exit command aims to stop xscreensaver temporarily so that it does not interfere with the upgrade process.

⚠️ Troubleshooting:
If the output of the sudo do-release-upgrade command looks like this:

Checking for a new Ubuntu release
There is no development version of an LTS available.
To upgrade to the latest non-LTS development release 
set Prompt=normal in /etc/update-manager/release-upgrades.

It means the official upgrade path isn’t fully open on your mirror yet. You can force the upgrade by appending the -d flag. Run this command instead:

sudo do-release-upgrade -d

Step 6: Follow On-Screen Prompts

During the upgrade process, you will encounter several prompts. Here is how to handle them:

  • Third-party sources disabled: You will see a notice that PPAs and third-party repositories have been disabled. Press Enter to acknowledge this (we will restore them later in Step 10).
  • Restart services during package upgrades without asking?: Choose Yes so the upgrade can proceed smoothly in the background without constantly interrupting you.
  • Modified configuration files: If prompted about replacing a configuration file, it is generally safest to choose Keep the local version currently installed (the default option). This preserves any custom system settings.
  • Remove obsolete packages?: Type Y and press Enter to clean up old, unnecessary packages and free up disk space.
  • General confirmations: For any other general prompts about package changes, type Y and press Enter.

Note: The entire process may take some time depending on your system performance and internet speed.

Step 7: Reboot After Upgrade

The upgrade tool will ask you to reboot at the end. Type Y and press Enter when prompted.

Step 8: Run the FunOS 26.04 Update Tool

After upgrading, run the FunOS update tool to apply system-specific improvements.

sudo rm -f /usr/bin/funos-update
sudo rm -rf /var/lib/funos-update
sudo rm -rf /tmp/funos-update
rm -f funos-update
wget https://raw.githubusercontent.com/funos-linux/funos-updates/main/ubuntu/26.04/funos-update
sudo install -m 755 funos-update /usr/bin/funos-update
sudo funos-update
rm -f funos-update
sudo apt autoremove --purge

What does this tool do?

  • Adds new wallpapers to /opt/artwork/wallpaper
  • Updates and enables the FunOS Plymouth theme
  • Replaces volumeicon-alsa-legacy with volumeicon-alsa
  • Installs Nitrogen
  • Updates the Mozilla Team PPA
  • Installs Dracut
  • Cleans up unnecessary desktop entries

Step 9: Restore Third-Party Repositories

During the upgrade, the do-release-upgrade tool disables all third-party repositories. Manually restoring them can be complex, as you need to re-enable independent repositories (like Google Chrome) while removing and freshly re-adding OS-specific Launchpad PPAs.

To automate this entire process safely, we have provided a script that parses your repository files, automatically re-enables global repositories, and re-installs Launchpad PPAs for the new 26.04 release.

Run the script using the following commands:

wget https://raw.githubusercontent.com/funos-linux/funos-updates/main/ubuntu/26.04/restore-third-party-repos
sudo chmod +x restore-third-party-repos
sudo ./restore-third-party-repos
rm -f restore-third-party-repos

Once the script finishes restoring your repositories, run an upgrade to pull in any updated packages they might have for 26.04:

sudo apt upgrade

⚠️ Note:
Some third-party repositories may not yet support Ubuntu 26.04. If the script encounters an error while adding a specific PPA, you may need to wait until its developer officially supports Resolute.

Step 10: Verify the Upgrade

Check that your system is now running the new version:

lsb_release -a

You should see:

Description:    Ubuntu 26.04 LTS

Step 11: Final Reboot (Recommended)

For best stability, reboot once more:

sudo reboot now

Conclusion

You have successfully upgraded to FunOS 26.04 LTS. This version brings improved stability, updated packages, and long-term support.

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