I recently started a new world to get the full feel of the new update. I have defeated the ender dragon about 8 times and I'm getting fed up. I reset the end twice, and on the most recent one I have I've defeated the dragon about 4 times now, I have 2 small portals that lead only to forests, and I've defeated the dragon twice more after these two have spawned, to no avail. No more portals will spawn. Am I doing something wrong? Does the game have to be on "Hard" difficulty to spawn more portals?