As far as I remember, 'version' attribute is not being used by jBPM core. If you want to have a new version of a process, it must have a different id.
jBPM5 supports 3 different ways to handle new "versions" of a process definition:
- New version is only applied to new instances: in this case, the old instances continue using the old definition and new instances use the new one. Here, the whole responsibility is thrown upon client (API user) shoulders: you must assure that both versions are in the kbase and that whenever you start a new process you are using the correct (newest) id.
- Process instance migration: jBPM5 has some API that allows you to migrate running instances of your processes to a newer version. Again, newer means different id. Once all your instances are migrated you no longer need the old definition of the process in your kbase. Process instance migration is now always a trivial process and in many cases is not possible to do it.
- The third approach can only be aplied to certain processes and consists in abort all the existing process instances and then start them again with the new definition (again, different id).
For more information please read this section of jBPM5 documentation: http://docs.jboss.org/jbpm/v5.1/userguide/ch05.html#d0e1768