While Mesa won't have OpenGL 4.2 support for some time, NVIDIA released an OpenGL 4.2 preview driver on Monday as soon as the Khronos Group had published the new specification. AMD yesterday has now released a beta Linux driver (of their Catalyst blob, nothing to do with open-source) that provides OpenGL 4.2 support.

Over on this support page is an OpenGL 4.2 beta Catalyst driver for Linux. This driver provides full support for OpenGL 4.2 / GLSL 4.2.

Beyond detailing the OpenGL 4.2 support, no other change-log is provided to know if anything else is changed compared to the latest public driver of Catalyst 11.7. Catalyst 11.8 meanwhile should be out within the next two weeks, but it's not known at this time whether that will have the GL 4.2 support integrated.