Yes, we are working on it. We will publish an updated beta in the next days, with Max 2012 support besides other changes. And since RailClone now supports VRay, the stable version will be ready when ChaosGroup releases the final version of VRay for 2012 (planned for end of April).
All upgrades are free for active subscriptions, but currently that includes all licenses of RailClone, because the plugin was released less than a year ago.