Bukkit

• Corrected concurrent modification exception (Ticket 1).

• Corrected Serialization issue (Ticket 2).

• Librarian doesn't automatically give reward to nearby player. A player who has launched a study must interact with the librarian to get his/her reward.

Not really a caveat but : The config.yml is not generated by default at server start. However, there's default values stored in the config.yml provided by the jar.