I've just made a mobspawner trap in my world after updating to 1.6.1, after the world (and chunk with the spawner) was created a while ago maybe in 1.2/1.3? In either case, the world was spawned before zombies dropped iron, potatoes and carrots.
Does this mean my mobspawner trap is never going to drop anything but rotten flesh? Or do I need to leave it longer?