It is up to each developer to choose the specific BB model numbers / major OS level combinations that they will support. Further, with BB10, it's not a matter of them porting their app from BBOS to BB10...they have to start from scratch. So, not all developers choose to support everything.
But, in any event, the best place to make your inquiry is with the app developer, for it is their responsibility.
Occam's Razor nearly always applies when troubleshooting technology issues!
If anyone has been helpful to you, please show your appreciation by clicking the button inside of their post. Please click here and read, along with the threads to which it links, for helpful information to guide you as you proceed. I always recommend that you treat your BlackBerry like any other computing device, including using a regular backup schedule...click here for an article with instructions.