I am currently working on app which is supposed to have Twitter integration. The app should also be built so it can be used on iOS 4.3 devices. We’d like to use the built in Twitter Framework on iOS 5 and possibly drop twitter support for iOS 4 devices (not sure about that yet).
The question is: Is this possible? As far as I can tell I can only link statically on iOS builds, which would mean an App built with the Twitter framework can not be run on an iOS 4 device. If this is possible, how would I got about linking the Twitter framework so I can get the app running on iOS 5 with built in Twitter support and ignore the Framework on iOS 4.
It is possible. Apple has introduced weak linking of frameworks that are not supported on older versions. You can get more details regarding weak linking here.
See one more similar question regarding weak linking here.
Hope this solves your problem.