Universal how to retrieve app from my old 4S and transfer to newer iphone?

[bluesbleu]

hi all, i have a problem here, i have an app that i have in my iphone 4S. previously it was stored inside the itune, but somehow since dunno when, the apps inside itune all disappear. now i cannot transfer the app to itune like before. so now how can i transfer the app from my old iphone to the newer iphone ? anyone??

 

[Apple_Robert]

If you bought the app from the Apple App Store and it is 64 bit compatible with the new phone, you will see it listed under purchased in the App Store app. If you look and don’t it under purchased on the new phone, that means the app was 32 bit and not compatible with a new phone.

 

[bluesbleu]

the app was download free but after a while, apple took it off the store.
i was thinking if there is any software or which older version of the itune can get this out from the old phone and transfer to the new phone.