This update should be compatible with worlds that were using New in Town version 2.17.3, as long as you also upgrade the world to Minecraft 1.21.2. This is due to some syntax changes regarding Attributes. As always, a backup is still recommended.

General:

• Updated to Pack Format 57 for Minecraft 1.21.2.
• Updated all attributes to remove prefixes per 1.21.2 syntax