Process version execution

My question is about process versioning with Bonita.

Let’s say I have a process with four activities (A, B, C, and D), and I create two instances of that process. So, when I change the process to another version with slightly different activities (A, B, D, and F), what happens to the two instances I previously created? Do I need to migrate them to the new process? Or do they become invalid?

From my understanding

The original processes will continue to execute as they are, only new instances of the process will execute with the new definitions.

You would have to create a routine to copy the data from old to new and then execute that to the point you want to resume from.

regards
Seán