I am dealing with multiple Rails applications at once some of which are funded right and some of which have ran into maintenance modes. I just wanted to have a pictorial representation of what is the state of each of the Rails versions, unfortunately, I cannot get one. So I spent half an hour trying to decode the Rails official releases page and came up with this.
If you closely observe, the Rails releases 3.0.x and 3.1.x are history (I don't even want to pull up data for releases before that). It is high time you plan to upgrade your stack to a minimum of Rails 4.2 before you loose all the goodness the Rails community has to offer. Yes, I know it is a herculean task for folks in 3.x in which case I recommend you to do a complete rewrite of your application piecemeal by piecemeal!
Data Source: http://weblog.rubyonrails.org/releases/