Being able to attach a version of the form to a version of the workflow

When we add a new action on an existing form/workflow (ex: adding "sending back to requestor" on existing "Approve/Reject" actions), When deploying the solution in PROD, the ongoing workflow instances are based on an older version that don't have that action but new forms will appear regardless of the workflow instance showing this new action/button. Would be usefull to specify when deploying that this form version only applies to new workflow instances.