Gnome 3.16

Upgrade to Gnome 3.16 in Ubuntu 15.04

Earlier in March this year, Gnome 3.16 stable version was released, but this version of Gnome was not made available for Ubuntu 15.04. Upgrading to Gnome 3.16 on Ubuntu 15.04 is currently possible but not recommended as you may likely run into issues since this release is largely untested fully. So ONLY do this if you really want to give it a try and ONLY on Ubuntu 15.04. Upgrade Gnome 3.