How to upgrade kubuntu 16.04 -> KDE neon

kubuntu-to-neon.md

This worked for me and might not work for your.

Try it at your own risk!

Add the neon repositories and install the neon desktop

$ wget -qO - 'http://archive.neon.kde.org/public.key' | sudo apt-key add -
$ sudo apt-add-repository http://archive.neon.kde.org/user
$ sudo apt-get update
$ sudo apt-get install neon-desktop

Upgrade everything. Repeat if necessary, until everything is really up to date and you have no held-back packages.

$ sudo apt-get update
$ sudo apt-get upgrade
$ sudo apt-get dist-upgrade

Updating programs to latest neon version works (after adding the ppa, the system can now find the latest versions of the kde programs)

but installing neon-desktop requires additional packages that are not installable on my system apparently

I imported to more gpg keys:

• Key 1 - signing key for Neon releases: https://keyserver.ubuntu.com/pks/lookup?op=get&search=0xDEACEA00075E1D76
• Key 2 - signing key for Neon packages: https://keyserver.ubuntu.com/pks/lookup?op=get&search=0xE6D4736255751E5D

The 2nd one (0xE6D4736255751E5D) was important to be able to add the neon repository to my apt lists and "apt update" successfully!

Oh. And I had troubles with KDE games, so I remove as much as I could, by doing:
sudo apt remove kmahjongg kmines kpat ksudoku libkf5kdegamesprivate1 libkf5kdegames7 libkf5kmahjongglib-data libkf5kmahjongglib5 kdegames-mahjongg-data-kf5 kdegames-card-data-kf5 libgamemode0 libgamemodeauto0 libkf5kdegames-data

and to make sure all dependencies are finally correct:
sudo apt-get dist-upgrade

Thanks for this. I had some minor problems upgrading from Kubuntu 20.04 LTS, but figured it out; Here's what I did in case anyone else encounters the same issue.

Note that once apt has been updated, sudo apt upgrade will no longer work, and you will have to use sudo pkcon update, as is the KDE neon way.

Every so often while doing sudo apt dist-upgrade, dpkg would error out, saying a package (from neon) tried to overwrite a file provided by another package (same, already install package from ubuntu), and it won't let you remove the package with sudo apt remove package. To get around this, for each broken package (I had ~20 in total):

1. sudo dpkg -i --force-overwrite /var/cache/apt/archives/package.deb (replace path with the one provided by the dpkg error message)
2. sudo apt --fix-broken install -y
3. sudo apt update && sudo apt dist-upgrade -y

Repeat these steps for every package that breaks in this way, and eventually, the dist-upgrade will go through with no errors. Do another sudo apt install neon-desktop and sudo apt autoremove to make sure everything is up to date. After a reboot, everything booted up without error.