twitterpro iPhone and iPad stops supporting devices that run on the mobile system iOS 9 and older, as can be seen from the notes for the latest update. So if you want to download Twitter app updates, you must have at least iOS 10. Of course iOS 10 cannot be installed on some Apple devices, so users of older iPhones and iPads (iPhone 4s, iPad 2, iPad third generation, first iPad mini and iPod touch 5) must say goodbye to Twitter updates.