Comment # 3 on bug 64443 from Kenneth Graunke

But that's still several months out, and you probably don't want to wait that
long.  In the meantime, you can do:
export MESA_GL_VERSION_OVERRIDE=3.2
export MESA_GLSL_VERSION_OVERRIDE=150

before launching OilRush...and it should work.  I haven't tested it
specifically but that works for both Unigine Heaven and Unigine Valley.

It might be worth adding a driconf setting to overrides these in a 9.1.4
release...not sure what people think about that.