I am planning to use advance version of JBPM i.e. JBPM 6.2. Currently my project is using JBPM 4.4 but there are issues with JBPM4 DB tables which are accessed internally by JBPM API. I need inputs regarding this udgradation activity:
Unfortunately the jBPM 4.4. codebase is an entirely different codebase. With jBPM 5 RedHat actually rebranded the old Drools Flow project to become jBPM 5. It uses an entirely new database and persistence design to store process and task data. So to answer your questions:
That is the $1000 000 question. I would suggest
4.1. Convert your jpdl files to BPMN files, and develop all new process in BPMN.
4.2. Migrate your system and implement the code to use the jBPM 6 RuntimeManager API and Task tables, perhaps using the tool mentioned in the link above)
4.3. For task lists, aggregate tasks from both the old and new tables
4.4. Keep both environments running in parallel until you have phased out all jBPM 4 processes.
Unfortunately, as far as I know, there is no quick and easy way to do it. Good luck!