I want to clarify Radiance because it says latest version as today of Radiance is 5.2.0 :
OpenStudio 2.4.0 supports Radiance 5.0.a.12, which is bundled with the OpenStudio installer; users no longer have to install Radiance separately, and OpenStudio will use the included Radiance version regardless of any other versions that may be installed on the system.