RenderMan for Blender is constantly receiving updates and bug fixes, so please refer to the RenderMan for Blender GitHub page for the latest nightlies version. 
Please note that these are untested versions, so use them at your own risk!

The GitHub page can be found here :
https://github.com/prman-pixar/RenderManForBlender

To Install, please ensure that you have already installed the released version of RenderMan for Blender from the downloads page in your forum account.  Once you have downloaded the latest code from the GitHub page, all you need to do is extract the .zip contents into your RenderMan for Blender installation folder.