I'm trying to install iBooks 3.1 on my iOS 8 because I prefer this old version. Anyway... At first iTunes, iTools and iFunbox said it couldn't be installed because it was already installed — meaning the iBooks 5.1 version from iOS 8. I managed to bypass that editing the ipa name values, it lookedat it was going to work for a while, even iTunes recognize the app with a different name. But the icon now appears on my iPad with the word "installing" below but it never does! iTools now gives me the "Installation failed: verification failed as the authority is in.." error. I wonder if anyone knows what other values I need to change in the ipa before installing on the iPad. Thanks.