If you add a new field: All old DCRs will not have that item in the XML. So as long as you don't modify them and re-deploy, there is no problem. When a user opens an old DCR in FormsPublisher, the new field will show up as blank and they can put the data in there. If you want to explicitly set a value to this field in the old DCRs, you need to write a script to do that.If you remove a field:Same thing. The old DCRs will still have that field until you open them in formspublisher and save them. If you re-save the DCR, the field will be gone.