I tried to keep the specification as compatible as I can with the existing APIs, however there are definately places where existing users are going to have to modify their code - specifically where it deals with Encoding and Validation. I believe these changes are absolutely necessary however to establish a good cross-platform specification. I also believe the migration path allows for the smoothest transition for end-users (developers) to make the necessary changes without completely breaking their existing implementations. This is similar to the path that Spring-Security took with it's 2.0 -> 2.5 -> 3.0 path where they did a very similar thing and I used their experience as the basis for the proposed roadmap.
--Chris Schmidt 02:23, 16 June 2011 (EDT)