As you may know, Krita is an open-source image manipulation software, allowing the user to either create pictures from scratch or edit existing images. It is good because it supports most graphics tablets very well.
Krita is developed on two branches, the Krita Testing one which is the first to receive new features and the regular Krita branch, where the stable versions get added.
Recently, the developers have updated their Krita Testing branch, adding some fixes and new features.
In order to successfully install Krita Testing on Ubuntu 15.10 Wily Werewolf, Ubuntu 15.04 Vivid Vervet, Ubuntu 14.10 Utopic Unicorn, Ubuntu 14.04 Trusty Tahr, Ubuntu 12.04 Precise Pangolin, Linux Mint 17.2 Rafaela, Linux Mint 17.1 Rebecca, Linux Mint 13 Maya, Pinguy OS 14.04, Elementary OS 0.3 Freya, Elementary OS 0.2 Luna, Deepin 2014, Peppermint 6, Peppermint 5, LXLE 14.04 and Linux Lite 2, you have to add the PPA to your system, update the local repository index and install the krita packages:
$ sudo add-apt-repository ppa:dimula73/krita
$ sudo apt-get update
$ sudo apt-get install krita-testing
Optional, to remove krita, do:
$ sudo apt-get remove krita-testing