OpenGL 2.1 and Intel
From Februrary 2017 onwards, Mesa (the open-source OpenGL
library) has dropped OpenGL 2.1 support for certain older and
less capable Intel graphic cards.
If you need to run applications that need OpenGL 2.1 (e.g.
blender) for these cards, it is possible to retro-fit the the
OpenGL 2.1 support.
This is done editing /etc/drirc and adding the following snippets:
<option name="stub_occlusion_query" value="true" />
<option name="fragment_shader" value="true" />