Kubuntu Backports PPA is activated by default in Netrunner 17.
I am sure Plasma 5.5 will come to this PPA though not immediately as it needs to be build and tested first.
Cool! I’ll wait then. I must say Netrunner 17 did install very smooth on Lenovo Yoga 2 Pro, way smoother then Netrunner 14 LTS. But the KDE 5.4.3 has a few very annoying bugs: Meta+Tab doesn’t work, activity manager doesn’t work that smooth too, you need to fix the audio settings, the window manager is bit quirky.