jBPM does not provide migrating processes to newer versions of a definition *out of the box* for various reasons:
- it does not know how to map ALL existing nodes to new ones, since a lot can change
- it does not know how to map ALL existing variables to new ones since a lot can change
- it does not know how to map tokens in running instances to nodes in the new processes since a lot can change
As you can see migrating processinstances is not practical, that's why there is no support out of the box
it *does* provide a low level api whith which you can manipulate almost everything. It's up to you to learn this api and use it at your own discretion.
ok i really understand those reasons. they will give me good arguments for our sales department
but suppose there will be only little changes...can i do for example a simple db update to make all processes the same version?
'simple is relative'
You have to find the primary key of the old and new tasknode and update the reference in task in the running instance. You'd have to do this for all the nodes.
otoh, you can try to change the current version of the processdefinition. Sometimes this is easier. There has been some discussion on this in the forums