Since Linux Mint 18 KDE uses the Kubuntu Backports we both thought it would be very productive if we asked both our users to help test our work, bring Plasma 5.8 to both Xenial and Yakkety. This update will also bring updated Frameworks 5.28 and Applications 16.04.3 so your favorite applications like Dolphin, Konsole, Kate will be updated with fixes, new features.
You should have some command line knowledge before testing.
Having a quick read about how to use ppa purge is also a big plus
How to test Plasma 5.8
Plasma 5.8.4 is currently in the Kubuntu Backports Landing PPA.
If your currently on Kubuntu 16.04.1 or 16.10 you can add this ppa with Konsole:
sudo add-apt-repository ppa:kubuntu-ppa/backports-landing
sudo apt update
Once that is complete:
sudo apt dist-upgrade
Once everything is done you can reboot.