For example, LibreOffice is available from FlatHub.org. So, I can install it with sideload. But I can also install it via the appcenter (flatpak search, strangely enough, doesn't find it).

Which of these options should I prefer in general?

3 Answers 3


After you install a Flatpak app via sideload then all apps from the Flatpak repo you downloaded it from (flathub.org) will show up in AppCenter so you shouldn't need to use sideload for subsequent apps from the same repo.

Personally I prefer installing Flatpak apps on elementary OS if you have the room on your HDD/SSD. The advantages are:

  • When you install a Flatpak app it includes all of it's dependencies in a runtime and when you uninstall it you can remove the app and the runtime easily as well. Contrast this with installing an app and a bunch of dependencies and uninstalling them when you no longer need the app (provided no other app is using them).
  • Since Flatpak apps do not depend on shared libraries there is no risk that an update to a shared library will break the app
  • Flatpak apps run in a sandbox and are therefore less likely to affect your system and other apps
  • Since Flatpak apps include their runtime they are able to run on just about any distribution. This makes it easier for developers to release new versions since they do not have to build for each distribution. The potential advantage here is that developers, who are mostly volunteers, can spend more time working on the app and less time distributing it.
  • Some argue that Flatpak apps are more secure but this is debatable. First, if you stick with the Ubuntu repositories then you can be reasonably assured that the apps are safe. If, however, you install additional PPA's you are trusting the sources. If you install Flatpak apps from flathub.org then you are trusting that flathub.org is keeping the bad guys out. Personally I trust Ubuntu, flathub.org, and carefully chosen third party repos when the former two don't have what I am looking for.
  • Since elementary OS is based on Ubuntu 18.04 the apps in flathub.org are typically newer versions. You can often, however, install later versions using apt-get by adding PPA's if you don't mind adding a bunch of them.

The disadvantages:

  • Since you have to install the runtime with the app Flatpak apps can consume a lot more space. Some apps share the same runtime which helps a little. I installed 12 Flatpak apps that have consumed a total of 5.7GB of space.
  • You have to download and install the first app (*.flatpakref) file via sideload before the rest of them show up in the AppCenter

My primary goal was to install as many of my apps as possible using the AppCenter and since eOS 5.1 has support for Flatpak apps I am accepting them as the preferred way to install apps that are not included in the default repositories.

A large part of the Linux community seems to be moving toward Flatpak, Snap, or AppImage. Whether or not it ever replaces traditional package management has yet to be seen. It could be just a fad.

That's the way I see it!

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  • Thanks for the detailed reply, but it leaves me with one question: When I'm using the appcenter, how can I distinguish the flatpak apps from the apt apps? RIght now, the apps I installed with sideload are not showing up in the appcenter at all!
    – Tim02130
    Dec 31, 2019 at 0:40
  • Did you try rebooting your computer? I have found that for some of the applications I can't distinguish if it is from flathub or the default apt repository while others have a dropdown giving you the option to choose which version you want. For example, search for Evolution and see if it shows up and if so if it gives you the option shown in the screenshot I attached to my post. Dec 31, 2019 at 3:50
  • Sorry to pick you. I'll address your first list by order. 1. That is like buying a light bulb with a power station in the package. 2. Been using eOS for a decade, never happened to me. 3. I want apps to affect the system (write/read files, etc). 4. I'm using effectively one distribution (the rest is docker) 5. Some argue.. 6. Only valid while the flatpaks keep getting updates, same with apt, yum, etc. I really fail to see the added benefit given all the drawbacks, disk usage specially is terrible. 10 apps 5GB sounds like a Windows thing. Oct 8, 2020 at 15:07

I would simply use apt-get install libreoffice.

KISS - Keep it Simple Stupid!

  • 3
    ...or just simply apt install libreoffice
    – Paul
    Dec 30, 2019 at 23:09
  • 1
    This is not an answer of the question, the question is about the Flatpak version but not what is the 'easiest' way to install libreoffice and there is no reason to be rude using some 'funny' abreviatures to call stupid somebody who probably you do not know.
    – Bo rislav
    Dec 30, 2019 at 23:51
  • @Borislav, Hello! Your participation is much appreciated! Please let me inform you that KISS - Keep It Simple Stupid is a principle. Yes, this is not to disrespect anyone. It's alright, misunderstanding happens. You can learn more about KISS here. Have a nice day!
    – Hasan
    Dec 31, 2019 at 5:02
  • @eric, welcome to elementary OS SE. Your participation is much appreciatedđź‘Ť Let me inform you that we love informative answers with step by step guide. Please try to post detailed information so that it is simple enough for someone with zero technical knowledge to easily understand. For example, you can explain why you are using apt. Have a nice day!
    – Hasan
    Dec 31, 2019 at 5:17
  • @Hasan, I see, but still this is not an answer of the question - what is the advantage of using sideload over flatpak over the appcenter but some another approach of installing the application. With the line above you cannot install a flatpak version of the application first, and again - the question is not about the easyest way to have some LibreOffice version but about the advantages and disadvantages of using the versions available.
    – Bo rislav
    Dec 31, 2019 at 8:58

What you 'should' or 'shouldn't' prefer really depends on your environment and your use case. However there is a set of questions which might help you to choose:

Do you want/need the newest version of an app and make sure it is always up to date vs. a well tested allbeit older version? If so Flatpaks and snaps are legit choices, but its important to keep in mind that they are not tested with Elementary OS and if you run a Snap or a Flatpak app you're trusting it to run because your system has Flatpak support, rather then that App being specifically developed and tested for eOS.

Do you custom theme your system? If you, like me are one to install custom themes and stuff like that on your system you might not want to use Flatpaks as they can only adapt to very few themes right now. Maybe in the future this will be a viable option, but as of today there's just not enough support for Flatpaks and custom themed systems to guarantee that it will not break the design principles around which you built your desktop.

How critical is system safety on your system? System safety is important to everybody that much is clear, but is it absolutely critical that no application has access to all parts of your file system and if not, which applications do you want to grant access to the latter? I for example, prefer my browsers and other internet related apps in a containerized format like snap or flatpak, but I will happily use debs and App Center Apps for the rest. Ultimately the question boils down to how cautious you are or have to be. I have no problems to install PPAs from devs I trust either, which however is something that I would never recommend over Flatpaks or AppCenter Apps if the second question is irrelevant to you.

So: Do you want the newest apps, relative system safety and you don't theme your system? Go for Flatpaks or Snaps. I'd recommend Flatpaks since they are now natively supported.

Do you want well tested apps that work and support for system themes and are tested with eOS? AppCenter is the place to be.

Do you think you can trust a developer enough to give an apllication full Disk Access, theme your system and want the newest version? PPAs are the way to go.

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