OpenGL version 2.0, released on September 7, 2004, is the sixth revision since the original version 1.0. Despite incrementing the major version number (to indicate support for high-level programmable shaders), version 2.0 is upward compatible with earlier versions, meaning that any program that runs with a 1.5, 1.4, 1.3, 1.2, 1.1, or 1.0 GL implementation will also run unchanged with a 2.0 GL implementation.