The path for episodes 50-53 were revealed upon the release of episode 49, which is an unusually large number of episodes. Usually, the path for 1 or 2 episodes is revealed at a time.
This is the first world in which the final level of the world is a multiple of 100 (Level 800).
On web version, this is the last world of 2014. The next world was released on 7 January 2015 when the first episode of World 10 (Flash) came out.