We haven't started working on it yet but we have it in our list of pending tasks. We will start working on this sooner than later but I can't give you an estimated date on this.
The reason is that it is not so quick and easy to update the Ruby main version (currently 2.1), since we have to update all of the stacks at once and make sure they all work properly, this way we ensure that users will not find any issues related to this.
We will try to let you know when we start working on this.
Let us know if you have any question.