I am using the open-source Mesa drivers (Gallium3D/radeonsi), which should support OpenGL 3.3, but don't seem to on my system.
According to this news article and this page recent Mesa versions should support OpenGL 3.3, but when I query for the OpenGL support on my system, I only see 3.0 supported:
$ glxinfo | grep "OpenGL version"
OpenGL version string: 3.0 Mesa 11.0.4 (git-ec14e6f)
I am using Fedora 23 with xorg-x11-drv-ati.x86_64 7.6.0-0.4.20150729git5510cd6.fc23 and these mesa packages. My graphics card is a Asus Radeon R9 280X DirectCU 2 TOP
So for me it seems like that something went wrong with the configuration, because theoretically it should be supported