dyld: Library not loaded, app requires AFNetworking 2.0.0 but provides version 1.0.0
I had this problem and tried a solution I found here https://github.com/CocoaPods/CocoaPods/issues/3903 - do a "Clean Build Folder" (Product menu -> hold down alt key and Clean should now say Clean Build Folder) and I also did a pod install but I don't think that matters.
I guess deleting the derived data folder also fixes the issue.