(K)Ubuntu 15.04 users are now able to install or upgrade to KDE Plasma Desktop 5.3 through Kubuntu-backports PPA.
KDE Community does not announce the release of Plasma 5.3 at the moment. According to the beta release, Plasma 5.3 comes with better power management, new Bluetooth applet, improved Plasma widgets, big steps towards Wayland support, and numerous bug-fixes. For more, go to kde.org
Install or upgrade to Plasma 5.3 in Ubuntu:
The new release has been made into Kubuntu Backports PPA, available for Ubuntu 15.04 and its derivatives.
To upgrade it in Kubuntu 15.04, open terminal and run below commands one by one to add the PPA and upgrade the whole system:
KDE Plasma 5.1 has been announced recently which brings back many popular features, a wide variety of improvements, and a large number of fixes.
KDE Team announced the Plasma 5.1 recently, which brings back many features that users have grown used to from its 4.x predecessor. Popular additional widgets such as the Icons-only Task Manager, the Notes widget and the System Load Viewer make their re-entry. Support for multiple time zones has been added back in the panel’s clock. The notifications have been visually improved, along with many bigger and smaller bug fixes.
For (K)Ubuntu 14.04 LTS, the Plasma 5 is available in the project Neon PPA. Installing it won’t overwrite your current installation, but the PPA is unstable and you may encounter bugs. Use it as your own risk!