It would be useful if the published version number of the app was available as a variable within the app. By displaying in a text field, you then have an immediate and dynamic way of seeing if a user is running the latest version.
We here you. We have started on this and exposing other information about the app which I know will be welcome news for many. However this is more complicated than one might think, requiring coordination between many different parts, and it will likely be many months until we complete it. There will be a blog post when available.