KDE Software includes Plasma, KDE Applications, KDE Frameworks and much more.

It is available with almost every Linux distro and increasingly in cross-distro packages.

Cross Distro Packages

AppImage Packages

AppImages allows you as user to get the latest version (or any version) of the software you need directly from its author and run it on your GNU/Linux distribution (almost any distribution). You only have to download the AppImage file, make it executable and run it.

Plasma itself is not being distributed as an AppImage yet but you can find a lot of KDE software packed in this format. Here is a list of those applications:

Krita is professional painting program.
Kdenlive is a Non-Linear Video Editor.
Kdevelop is a cross-platform IDE for C, C++, Python, QML/JavaScript and PHP.

Flatpak Packages

Snap Packages

KDE Snap packages work on most Linux distros and are built by the KDE neon project.

Distro Packages

AOSC OS

AOSC OS provides this version of KDE Applications in the community repository

AOSC OS provides the newest KDE Applications, Frameworks and Plasma packages in its main repository (pre-configured for official releases). Users can get updates to the newest KDE Plasma and KF5 components as soon as they are made public.

Users can also get newest pre-configured KDE releases from the AOSC OS release directory.

Arch Linux

Arch Linux provides the latest stable packages in the [extra] repository

# pacman -Syu
# pacman -S plasma-meta

or

# pacman -Syu
# pacman -S plasma

Beta releases are available in the [kde-unstable] repository.

Chakra

Chakra provides KDE software packages in our official repositories. Plasma is the default desktop environment on our live media.

Gentoo Linux

Applications release ebuilds are available in the main repository. See the Gentoo wiki KDE article for general information.

Applications stable and master branch ebuilds are available in the supplemental KDE development ebuild repository.

KaOS

Plasma 5 is the default option and all installs automatically run the latest Plasma 5 release. Regularly updated ISO images are available on the Download Page

KDE neon

KDE neon builds all the latest KDE software

User Edition contains builds from latest releases
Developer Unstable edition contains builds from latest Git in master branches
Developer Stable edition contains builds from latest Git in stable branch including beta branches
KDE neon Docker Images can be used to test different versions on any distro

Exherbo Linux

We currently provide Plasma 5 packages (usually the latest stable release) in the kde repository. They can easily be installed with the help of the plasma set:

# cave resolve plasma*

We also offer packages for beta releases or packages tracking master, but you'll need to unmask them:

# echo 'plasma pre-release' >> /etc/paludis/package_unmask.conf

or

# echo 'plasma scm' >> /etc/paludis/package_unmask.conf

respectively.

Fedora

Supported Fedora releases get Plasma updates as soon as possible. Keep your Fedora installation updated and you are good to go.

See https://apps.fedoraproject.org/packages/plasma-workspace for details on the progress of Plasma updates.

Kubuntu

Kubuntu 18.04 LTS was released in April 2018 with Plasma 5.12.4 LTS. Plasma 5.12.5 is already available in updates PPA. 18.04 will be supported until April 2021.

Kubuntu 18.10 Cosmic Cuttlefish,includes Plasma 5.13.5. The live ISO is available for download, and Plasma 5.14.3 can be installed via the Kubuntu backports PPA. Support until July 2019.

Kubuntu 16.04 LTS was released with Plasma 5.5.3. Then, you can upgrade to 5.8.9 via backports. Support until April 2019.

Kubuntu KCI provides the latest from KDE git. Add ppa:kubuntu-ci/unstable for testing. WARNING: Do not use on production systems. Ensure that you have ppa-purge installed in case you must roll back to your previous state. Zero guarantees that will fix a broken system.

Mageia

Mageia Cauldron is updated to new Qt, KDE Frameworks, Plasma Desktop and KDE Applications release almost as soon as they're released.

Plasma Desktop is one of the default desktops in Mageia. You can it on your hard disk or try it from the system.

OpenMandriva

OpenMandriva Cooker is updated to new Qt, KDE Frameworks, Plasma Desktop and KDE Applications releases as soon as they're released.

The latest OpenMandriva release version gets backports of new KDE software after it has been tested in Cooker for a while, and is usually a few weeks behind Cooker in updating.

Plasma Desktop is the default desktop in OpenMandriva. You do not need to run any extra commands to install it.

openSUSE

Users of openSUSE Tumbleweed get the latest KDE software directly after release, build testing and openQA testing. Just keep your system up-to-date.

The latest stable openSUSE release (Leap 42.2) receives updates to Frameworks on as part of distribution updates. As this process involves the distro QA team, usually there is a delay between a release and the actual availability of packages.

openSUSE Leap 15 ships the LTS version of Plasma (5.12).

Additional repositories provide latest (beta/rc/stable) releases and automated builds from git master for both Leap and Tumbleweed.

Additional package repositories

You can use the repositories maintained by the openSUSE KDE community team to get updated packages faster. Stable Frameworks releases are tracked in the KDE:Frameworks5 repository (both Tumbleweed and Leap).

Slackware

You can get Plasma 5 packages for Slackware-current from Alien BOB's repository. These packages will replace KDE 4 if you have installed that. Read all about it on Eric's blog