Several versions of the OpenGL ES specification now exist. OpenGL ES 1.0 is drawn up against the OpenGL 1.3 specification, OpenGL ES 1.1 is defined relative to the OpenGL 1.5 specification and OpenGL ES 2.0 is defined relative to the OpenGL 2.0 specification. This means that, for example, an application written for OpenGL ES 1.0 should be easily portable to the desktop OpenGL 1.3; as the OpenGL ES is a stripped-down version of the API, the reverse may or may not be true, depending on the particular features used.