This release contains a new REST framework implementation using Spring MVC instead of Restlet. The REST urls haven't changed, so all REST clients should still be working. We did however remove the deprecated legacy REST urls.
In addition, we also added a new lock free job executor, which should improve the number of jobs that can be executed per second with a magnitude of 100. You can look for more details at this wiki page https://github.com/Activiti/Activiti/wiki/Notes-on-the-new-Actviti-Jobexecutor-(Oct-2014) . Note that the implementation of this new job executor is not yet complete and it's lacking exclusive job support and being aware of suspended process instances.