How to enable Flatpak in Kubuntu 24.04 LTS

[Schwarzer Kater]

If you want to use Flatpaks complementary to or instead of Snaps you will have to enable Flatpak support in Kubuntu 24.04 LTS first.

You can do this either mainly in the graphical user interface (GUI) --> see A.
or
completely in the command-line interface (CLI) --> see B.

---

A. Here is a step-by-step tutorial for the graphical user interface (inspired by claydoh's helpful screenshots in many of his posts I decided to also add screenshots this time ):

1. To add the Flatpak support for the system plus the support for the Discover software center
   --> open Discover from your --> Application Launcher --> System and --> click on Settings (in the lower left area).
   
   Now on the right side --> click on the [Install] button under the "Missing Backends" section (screenshot #1), enter your password (screenshot #2) and wait for a moment.
   
   
   At this point you have already installed two things:
   a) the system's Flatpak support itself (which can also be used in CLI, see flatpak --help and man flatpak in Konsole),
   b) the Discover support for Flatpak to find, install, update and remove Flatpaks with the Discover software center.
   .
2. To enable the Flathub repository for Flatpaks (to actually have a pool of applications to choose from)
   --> close and reopen Discover and --> click on Settings again.
   
   Now -> click on the button [Add Flathub] on the right side (screenshot #3) and enter your password (screenshot #4).
   
   (The Flathub repository for Flatpaks is the largest one and is supported by e.g. KDE and GNOME - you can enable other Flatpak repositories like e.g. the one from Fedora or from individual developers later on if you wish to do so.)
   
   Wait a moment for Flathub to appear in the list of sources (screenshot #5).
   
   
   --> Close Discover.
   .
3. To be able to manage Flatpak permissions with System Settings
   you will have to use the Konsole terminal emulator to install the Flatpak Permissions Settings module for System Settings.
   
   --> Open the Konsole terminal emulator from your --> Application Launcher --> System and enter
   sudo apt update && sudo apt install kde-config-flatpak and your password (screenshot #6).
   
   
   
   Congratulations: if need be you can manage Flatpak permissions in --> Application Launcher --> Settings --> System Settings --> Applications in the future.
   .
4. Restart your system or at least log out and in again to apply the changes.

Done - you can now use Flatpaks and manage them with Discover and their permissions with System Settings (screenshot #7 - an example of the very good digital travel assistant KDE Itinerary Flatpak which shows its required default setting for Internet access).

Or you can do all of that in Konsole, of course.

Please know that both Flatpaks and Snaps use up more space of your storage medium than programs "traditionally" installed by APT.
Flatpaks have some advantages and disadvantages that Snaps don't have and vice versa.

---

B. Here is a step-by-step tutorial for the command-line interface:

1. Open the Konsole terminal emulator from your --> Application Launcher --> System and enter
   sudo apt update && sudo apt install flatpak plasma-discover-backend-flatpak kde-config-flatpak and your password
   
   This will install three things:
   a) the system's Flatpak support itself (which can be used in CLI, see flatpak --help and man flatpak),
   b) the Discover support for Flatpak to find, install, update and remove Flatpaks with the Discover software center and
   c) the Flatpak Permissions Settings module for System Settings to manage their permissions in --> Application Launcher --> Settings --> System Settings --> Applications
   .
2. To enable the Flathub repository for Flatpaks (to actually have a pool of applications to choose from)
   in Konsole enter
   flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo and your password
   (The Flathub repository for Flatpaks is the largest one and is supported by e.g. KDE and GNOME - you can enable other Flatpak repositories like e.g. the one from Fedora or from individual developers later on if you wish to do so.)
   .
3. Restart your system or at least log out and in again to apply the changes.

Done - you can now use Flatpaks and manage them and their permissions in Konsole.
Or you can do all of that with Discover and System Settings, of course.

Please know that both Flatpaks and Snaps use up more space of your storage medium than programs "traditionally" installed by APT.
Flatpaks have some advantages and disadvantages that Snaps don't have and vice versa.

[Snowhog]

PS: Sorry for the numbering of the screenshots - I realized too late that I could only post five…

I've adjusted the value for Maximum Attachments per Post for Valued Contributors.

[Schwarzer Kater]

Cheers! I added the screenshots regarding "enter your password" again. :-)