1) automated script that

• gets the jbpm schema create scripts from a (configured) previous version from jbpm from the maven repo.
• create previous version schema in db (preferably leverage existing jdbc.properties handling)
• run the hibernate update tool to calculate DDL upgrade script
• optionally add the capability of running the test suite against the migrated DB schema

2) in one go it is probably easy to add an automatic diff report between the plain sql ddl schema generation scripts. that can be used to verify if there are any other changes then the ones that hibernate distills in the schema update tool