Hmmm...
If it was you who made the PanelView application, then you allready have the same version of the software.
If you are asking to be able to load somebody elses project from the PanelView and still be able to open it with an older version of the software - then I think you are asking for too much.
It's a great feature to be able to upload, but you can't ask the software programmers (the creators of the HMI software I mean) to look backwards all the time, they should be able to add new features with backwards compatibility (without having to think too much about forward compatibility).
For PLC's you can typically convert the code to a simple format (statement list or the likes) and then load this into the old software if possible.
But HMI's are all about communication drivers, fonts, colors, graphics, animations and so forth - its too difficult to make forward compatible.