If you want to try the new version of KDE Plasma version 5.1 on Ubuntu 14.04 or Ubuntu 14.10, you can easily add the following PPA Repository to your system and install KDE Plasma 5.1 on it.
This KDE Plasma 5.1 PPA Repository supports other Ubuntu derivatives system such as Linux Lite, Linux Mint, PinguyOS 14.04, and many others. To add the PPA and install KDE Plasma 5.1 on Ubuntu 14.04 and Ubuntu 14.10, use the following commands:
sudo add-apt-repository ppa:neon/kf5
sudo apt-get update
sudo apt-get install project-neon5-session project-neon5-utils project-neon5-konsole project-neon5-breeze project-neon5-plasma-workspace-wallpapers