The Arch Linux developers, through Antonio Rojas, published a brief announcement on the project's website to inform all users of the lightweight and highly customizable computer operating system about some modifications in the KDE packages.

According to Mr. Rojas, it appears that there's no one left to maintain the KDE 4 packages in the main software repositories of the GNU/Linux distribution, and the unanimous decision of the Arch Linux devs was to remove them from the repos, because it is becoming very difficult to keep both KDE 4 and KDE Plasma 5 up-to-date.

Also, the Arch Linux developers believe that the recently released KDE Plasma 5.5 desktop environment is stable and mature enough to replace the KDE 4 variant, which will be automatically upgraded to the latest KDE Plasma 5 version in users' computers in the next few days, hence the announcement.

"Since the KDE 4 desktop has been unmaintained for several months and it's becoming increasingly difficult to support two versions of Plasma, we are removing it from our repositories. Plasma 5.5 has just been released and should be stable enough to replace it," said Antonio Rojas. "KDE 4 installations will not be automatically upgraded to Plasma 5."

Therefore, to avoid any complications, Arch Linux users are urged to either upgrade their KDE 4 installations to the KDE Plasma 5.5 packages or switch to a maintained alternative of the KDE 4 branch as soon as possible. Make sure that you also backup all of your custom configurations and other important files.

For upgrade instructions, please see the Arch Wiki.