I am about to upgrade to a new Iphone 5s. I currently use my iphone 4 for listening to spotify songs offline while running. Can I continue to use my iphone 4 to listen to spotify offline after I change my wireless account over to my new Iphone 5s? Can I sync spotify with my old phone via my desktop in order to maintain my playlists without a connection to a wirless account? Or does my old phone need to be able to connect to the internet?