OpenGL 2.1 has programmable shaders. GLSL shaders were moved to core in OpenGL 2.0 version. See here: <a href="https:&#x2F;&#x2F;www.opengl.org&#x2F;wiki&#x2F;History_of_OpenGL#OpenGL_2.0_.282004.29" rel="nofollow">https:&#x2F;&#x2F;www.opengl.org&#x2F;wiki&#x2F;History_of_OpenGL#OpenGL_2.0_.28...</a>