#575 Reworked the language files to use the .yml format instead of the .properties format. You can now specify where each message is displayed like CHAT, TITLE, ACTIONBAR. If you do not need the message, you can hide it completely using HIDDEN. Your existing language files will not be deleted but they are no longer used. You need to manually transfer your changed messages to the new file.
#574 Added a new arena.yml option interactionCoolDownPerPlayerMs, which allows to define a ball click cooldown per player. Use the /blockball toggle <arena> command twice to transfer the property to your arena file.