To commentate on the new and rebuilt Messages, the format of all your existing messages need to be cleaned up and restructured. Don't worry, you won't lose any existing messages. The app just updates the keys paired with each parameter to the new renamed parameters on the backend.
What about previous versions of the app?
The previous versions of Social Dummy (v4.5.8 and earlier) are not compatible with the new structure. So once you reformat, - you can't go back to the old structure. In doing so, if you did go back with the new structure the messages will be blank until you go back to the latest version of v5.0 or later.