Solution: An upgrade from ’disco’ to ’focal’ is not supported with this tool

If you are looking for a way to upgrade your Ubuntu from 19.04 (disco) to 20.04 (focal) without a fresh install, then this information is for you.

Problem: When I use the Software Upgrade graphical tool, I get the following error.

    Can not upgrade: An upgrade from 'disco' to 'focal' is not supported with this tool.

When I run "do-release-upgrade", I get the following output:

    Checking for a new Ubuntu release...
Your Ubuntu release is not supported anymore. For upgrade information, please visit: http://www.ubuntu.com/releaseendoflife
    Get:1 Upgrade tool signature [1,554 B]
    Get:2 Upgrade tool [1,337 kB]
    Fetched 1,338 kB in 0s (0 B/s)
    authenticate 'focal.tar.gz' against 'focal.tar.gz.gpg'
    extracting 'focal.tar.gz'
    Reading cache
    Checking package manager
    Can not upgrade
    An upgrade from 'disco' to 'focal' is not supported with this tool.

How to upgrade Ubuntu from 19.04 to 20.04 LTS?

There is no direct 19.04 to 20.04 upgrade path. This is the consequence of not upgrading when your do-release-upgrade windows were open. You should have migrated from 19.04 to 19.10 sometime between October 2019 and January 2020, then from 19.10 to 20.04 sometime between April 2020 and July 2020.

Solution: The following steps use the original Debian method of manually editing your sources, then dist-upgrade. I have personally tested it with my Ubuntu 19.04 and it worked like a charm.

Step 1: Change Your Sources

If you've selected the traditional Debian path, you're going to need to change the /etc/apt/sources.list file and replace the name of your previous release with bionic. So, if you're on 18.04, replace every instance of bionic with focal. If you are on 19.04, replace disco with focal. If you currently have 19.10, replace eoan with focal.

This process can be automated by using the following sed command:

For Ubuntu 18.04

    $ sudo sed -i 's/bionic/focal/g' /etc/apt/sources.list

For Ubuntu 19.04

    $ sudo sed -i 's/disco/focal/g' /etc/apt/sources.list

For Ubuntu 19.10

    $ sudo sed -i 's/eoan/focal/g' /etc/apt/sources.list

Then, look in /etc/apt/sources.list.d/. Change any files in there the same way.

Step 2: Ubuntu Upgrade

Now, you can run the Ubuntu dist upgrade. First, update the Apt sources. Then, run the Ubuntu upgrade.

    $ sudo apt update && sudo apt -y dist-upgrade

The upgrade should take a bit of time and requires several restarts. Chances are, every package on the system will be upgraded. When the Ubuntu upgrade does finish, reboot the system. When the system comes back up, you'll be running Ubuntu 20.04 LTS. Just check your Ubuntu version with the following command. You should see something like:

    $ lsb_release -crid

Distributor ID: Ubuntu
Description: Ubuntu 20.04 LTS
Release: 20.04
Codename: focal