I am almost positive that it will work, the ps3 is still very widespread, and the ps4 will take some time to catch up, so the only way for Sony to make its people happy is to allow this, and not to mention the PlayStations both use psn, so they are going to be interconnected, the same as the call of duty and other games, they want to make money, and to do that, connecting the systems is the only option.