The OpenGL ecosystem is particularly fragmented. There is a lot of different OpenGL implementations but none of them is reaching the same level of features.
NVIDIA implements OpenGL 4.3; AMD implements OpenGL 4.2; Intel implements OpenGL 4.0; Apple implements OpenGL 3.2; and MESA implements OpenGL 3.1. On top of this, even if there are OpenGL 3 and OpenGL 4 hardware supporting each minor revision of the specifications, a lot of OpenGL 4 extensions are available on OpenGL 3 hardware.
It can be complicated to navigate into the OpenGL extensions and optimize our application to maximize the use of OpenGL features. I created an OpenGL features matrix to resolve this issue. It summarizes for each architecture the list of supported extensions.