The process of moving an application from our old stable API to the new Unified EFL may take some time. Enlightenment is probably the largest EFL application so we know how complicated this could be! To ease the transition we are ensuring that the APIs are interchangeable.
For the foreseeable future all EFL releases will contain both the Legacy and the Unified APIs meaning that you can upgrade once you feel that our new APIs are ready for your usage. The benefits of moving over should be compelling, but as usage varies between apps we will continue to support the legacy API for all our users.