TwiFixer is a basic tweak that allows the Twitter app on iOS 5 to work again by disabling certificate pinning, and allows the app on iOS 7 to work again by fixing a crash bug. It does not yet fix logins on the iOS 5 app, so you need to log in to Twitter through the iOS settings app (iOS 5 only).

(This tweak was last updated in 2019, and will likely not do everything required to fix Twitter in the year 2022 and beyond.)