Hey Jose -
Nice job catching that comment :) There are no documented plans on what to expect for this version. I can tell you at a high-level some of the things I'm going to be tackling, but I'm not yet committing to any of them -- it's all still a work in progress...
* Major refactor of underlying implementation. The library has gotten complex and it's time to take a fresh look at refactoring it. This is the reason the version will bump to 2.0.0 as it'll potentially break any libraries that have extended state_machine. However, it will make it easier to extend state_machine. This is in development, likely to appear in the next month or two.
* Variety of changes / fixes to callback underpinnings -- callbacks will be more consistent with how they behave in each ORM
* Support for additional ORMs (toystore is on my short list)
* Addressing most, if not all, of the remaining issues filed in GitHub
* Potentially major changes to the way tests are written, especially for ORM integrations
All in all, there should be very few, if any, changes to the existing public API. There will be new features and integrations, but a significant portion of this will be around refactoring and fixing. I will continue to support the same Ruby and ORM versions supported today.
I don't expect to see the final 2.0.0 release until Q4 this year. We'll continue to do incremental updates to the 1.2.x series, but my focus will be on continuing to make state_machine a clean, rock solid implementation.
Hope this sheds a little light! (and, hey, it was helpful for me to write it down too :))