Is this a browser form? I don't think this applies to browser forms, because when the form is rendered, it is connected to a template (XSN), so unless you have multiple templates (i.e. separate content types), it has no way to maintain the previous schema/layout. It can't know what this is - it can only call from the existing template. With client forms, the XSN is cached locally, so the user gets to decide whether they want to update their local copy to the new version. They can refuse, but if they click "new," then it downloads and caches the new copy of the template, which causes existing forms to open with the new template as soon as the next one is opened.
To keep old forms using their template, I believe you'll need to have a separate template for each version. Why do you want so many different versions of the same form? That's not typically how InfoPath is used.