If you use an iPhone 4S or iPad 2 as a dedicated music player, e-reader, or retro game console, modern app versions won’t install. You need the last compatible iOS 6 IPA for that app.
: Without these archives, classic games and apps removed from the App Store would vanish forever. Hardware Longevity ios 6 ipa files
Many archived IPAs are "encrypted" and will ask for the original uploader's Apple ID. Use Clutch on a jailbroken device to "crack" and decrypt these apps for personal use. If you use an iPhone 4S or iPad