This has not really been a problem as I continued developing my app and extending the data types. I have launched an alpha and have been changing the data and incepted data and links, without much pain. What happens is when you create a new link (say a new link between message and post) some previously created data links may get orphaned, but you can “gracefully” handle such things in execution. You can also create workflows. For example, we didnt have notifications at launch. We then added notifications later, and had to write a quick one-time workflow to send out pooled notifications from the past. But of course, all this is fine in alpha/testing, probably not in full-deployment.