title: Which Ruby on Rails is compatible with which Ruby version?
body: <p>I have an old 2.1.1 Ruby on Rails application, with the system upgraded to use Ruby 1.8.7. It originally used 1.8.5 or so.</p>
  
  <p>I want to upgrade it to Ruby 1.9.x for performance reasons, and possibly to a newer Ruby on Rails as well.</p>
  
  <p>I cannot find any easy chart of compatibility between different Ruby versions and Ruby on Rails versions.</p>
  
  <p>Will 2.1.1 work with Ruby 1.9.x? If not, how far do I need to upgrade it first, and what kind of issues am I likely to encounter? My application does complicated things to database layer, but the rest is fairly straightforward.</p>