The monthly KDE update, 4.11.2, has been released earlier today, fixing over 70 bugs, including KWin, Dolphin and the personal information manager application Kontact.
To try it in (K)Ubuntu, use the Kubuntu Updates PPA:
sudo add-apt-repository ppa:kubuntu-ppa/ppa
sudo apt-get update
sudo apt-get upgrade
sudo apt-get update
sudo apt-get upgrade
This will install the latest KDE version available in the PPA.
