Maintenance for the week of November 3:
• NA megaservers for maintenance – November 3, 4:00AM EST (9:00 UTC) - 12:00PM EST (17:00 UTC)
• EU megaservers for maintenance – November 3, 9:00 UTC (4:00AM EST) - 17:00 UTC (12:00PM EST)
• ESO Store and Account System for maintenance – November 3, 4:00AM EST (9:00 UTC) - 12:00PM EST (17:00 UTC)
• https://forums.elderscrollsonline.com/en/discussion/684716
To be precise, the current Mac minimum requirements have been in effect since 4/29/2015. The most current version with a date stamp can also be found here. OpenGL 4.1 is not yet in active use by the most recent ESO client version, but will be in a future upcoming update (no ETA announced as of yet).
Please refer to this extensive Apple FAQ on which Mac models and OS X versions are capable of being upgraded to the current OS X 10.10 Mavericks. There's also a chart showing which GPU models support OpenGL 4.1 in OS X 10.9 and up.