How do I transfer a single app with data from one iPhone to another?



I just got a new iPhone, and wanted to start "fresh", that is, only installing the app I actually use - not the full pile of junk that was lying around on my old iPhone.
Therefore, I opted not to set up the new iPhone ( from the old one's backup, but instead, downloaded what I wanted from the App Store.
Now I see that one of the apps on the old phone is subscription based, so that I need a password to use it. The password is stored, so I don't have to enter it on my old phone. But I do not know that password, and for various reasons, I'm unable to use the app's forgotten password function.
So I would like to transfer that single app, including its data (password) to my new phone. How can I do that?

  • SVS Sound Subwoofers
  • Experience the Martin Logan Montis