Generally we recommend against retroaction--the assumed model is that every workflow finishes on the code version it started. This is managed automatically in our hosted version (DBOS Cloud) and there's an API for self-hosting: https://docs.dbos.dev/typescript/tutorials/development/self-...

That said, we know sometimes you have to do surgery on a long-running workflow, and we're looking at adding better tooling for it. It's completely doable because all the state is stored in Postgres tables (https://docs.dbos.dev/explanations/system-tables).