Is there a way to transfer an app from a device to another one (App no longer on the app store)? I have and use Photosynth regularly on an iPhone 4s.
I bought a 5s last week and when i wanted to install the app on it i realised that the app isn't on the app store anymore.

Is there a way to transfer it from the 4s to the 5s ?

Thanks
First you want to do a back up of the 4s. Then you want to follow these steps:

Once you've finished that, you want to load the iPhone 5s with the backup.

And then you should be good to go. These are from apples website: here
Hope it helps!