This version is not compatible with Minecraft version 1.20.1 or older. It should be compatible with New in Town worlds upgraded from 1.20.1 and to this New in Town version, but you should still create a backup of your world first, just in case.

General:

• Updated Pack Format to 18.
• Updated all mobs that get summoned with Potion Effects to use the new 1.20.2 format.
• Updated most methods of randomness to use the new /random command. A few use-cases still use older methods, primarily those that are intended to be randomly based on UUIDs, such as the player's ship sail color.