It helped for Ruby. Ruby released 1.8.6 and 1.9.1 which were both two intermediate steps between Ruby 1.8 and 2.0. 1.8.6 beibg similar to 1.8.4 but with many ad

It helped for Ruby. Ruby released 1.8.6 and 1.9.1 which were both two intermediate steps between Ruby 1.8 and 2.0. 1.8.6 beibg similar to 1.8.4 but with many added 2.0 features and 1.9.1 which was almost 2.0 but with some deprecated features in it. I got to experience both and the Ruby 2 migration was much smoother than the Python 3 one. EDIT: To be clear, Ruby did not make it literally possible to run both 1.8 and 2.0 in the same code base but with just a few conditional statements and avoiding to use non-backported 2.0 features it was easy to write libraries which could run in both 1.8.6 and 1.9.