Remarkable 2.2.x series was made of frequent releases with deprecation warnings to consolidate the API. Until we get into 2.3, we improved support for ActiveRecord validations, fixed some bugs and made some changes, so we are safe and clear to work on new features and new matchers.
We also run our specs suite in Rails 2.3.x and Rspec 1.2.0 to assure that everything is working as supposed, and they are. :)
Thanks for everyone who collaborated, we are getting solid as rock. :)