Upgrading EOL ubuntu systems

Today was another upgrade time. Nothing was out of the ordinary until I reached a node with an EOL ubuntu installed 23.04 (Lunar Lobster) which to my good luck went EOL yesterday!

While we will mostly be following the steps from the guide EOLUpgrades I'll document the process here for the future.

vim /etc/apt/sources.list

Edit all lunar entries with noble ones. Since we are aiming for the latest LTS version in this case.

apt-get update
apt-get dist-upgrade
do-release-upgrade

Based on the guide I should run the last command but it tries to upgrade to the next version (non-LTS) which I don't want...

Since I tried the command before changing the deb packages and got a message similar to:

An upgrade from 'eoan' to 'focal' is not supported with this tool.

I'll try the upgrader path too

wget http://archive.ubuntu.com/ubuntu/dists/noble-updates/main/dist-upgrader-all/current/noble.tar.gz
mkdir upgrader
tar -xaf noble.tar.gz -C upgrader
cd upgrader/
./noble

While the guide says to change the debs first and later try this steps it seems to mee that it should be done the other way

As a fun extra point while upgrading plex uninstalled itself... no idea why other than possible the deb repo got unlisted and it got removed as a side effect. Not sure if that's possible to avoid but sucks quite a bit.

The correct update steps?

Run do-release-upgrade if the upgrade path is not supported download the upgrader tool for the version you want to upgrade into and execute it.

wget http://archive.ubuntu.com/ubuntu/dists/noble-updates/main/dist-upgrader-all/current/noble.tar.gz
mkdir upgrader
tar -xaf noble.tar.gz -C upgrader
cd upgrader/
./noble

Profit