If you are using Ubuntu 14.04, you will have GIMP version 2.8.10 from the official repository. If you want newer version, there is 2.8.16 version from Otto's PPA for Ubuntu 14.04. Thanks to Otto. To install it, follow below instructions.
sudo add-apt-repository ppa:otto-kesselgulasch/gimp sudo apt-get update sudo apt-get install gimpThe PPA page is here.