First of all running swu_obuf is probably run automatically assuming you have a reasonable system version. If not, running it is usually a good idea.
Anyhow, pay attention that workflow templates are version dependent but the workflow container and workflow objects/class are not. To be more specific,a workflow template that started running in a specific version will continue running in that version, and a version is set every time you transport a workflow into a system. The objects methods or attributes however, will run in the active (last) version only.
You most make sure that your object support earlier versions of the workflow templates, don't add mandatory importing parameters for example.