Apple announced details of OS X 10.9 "Mavericks" today. For anyone who writes cross-platform graphics software, one of the biggest bits of news was that it will finally support OpenGL 4. Specifically:
OS X 10.9 will support the OpenGL 4.1 Core Profile
This info comes from their release notes. I haven't been able to find any info about supported extensions yet.
While welcome, the news is still a bit disappointing. OpenGL 4.1 is now a 3 year old standard, so I'd hoped for something a bit more recent. I believe the Intel HD4000 and HD5000 chips used the MacBook Air & Pro only support up to OpenGL 4.1, so I guess that played a part in the decision.
OS X will be still be the lowest common denominator for OpenGL, relative to Windows and Linux; but at least the denominator is not quite as low any more!