The Neptune distribution runs on a Debian base and provides users with an up to date KDE Plasma desktop. The Neptune project provides its users with a newer version of Plasma than Debian's Stable branch does, so the Neptune developers have created a script which allows Debian users to install Neptune's Plasma packages. "As we got so many requests from Debian 9 Users that wanted to upgrade their installation of Plasma 5.8 to Plasma 5.12 we created an upgrade script that will take care of importing our kde-repo into the system and upgrading the desktop to Plasma 5.12. All you need to do is download the script make it executable and execute it as root. (If you want to know what the script is doing take a look at its sourcecode first.)" The upgrade script can be downloaded from the Neptune news post.