[1] In 2012, it formally replaced Apple's internal X11 app for OS X Mountain Lion (version 10.8).

This includes numerous scientific and academic software projects.

[2] In Mac OS X 10.4 Tiger, Apple's X11 implemented X11 protocol release 6.6 (X11R6.6).

The current version of XQuartz is a DDX (Device Dependent X[5]) included in the X.Org Server and implements support for hardware-accelerated 2D graphics (in versions prior to 2.1), hardware OpenGL acceleration and integration with Aqua, the macOS graphical user interface (GUI).

As of version 2.8.0, XQuartz does not provide support for high-resolution Retina displays to X11 apps, which run in pixel-doubled mode on high-resolution displays.