Experimental features. Create backups of your world before using.

• Added cython mesh generator #392
• Improved world closing #570
• Improved threading #571

Amulet-Core Changes

• Added a cython leveldb wrapper for a bit more speed Amulet-Team/Amulet-Core#177
• Rewritten the Java chunk interfaces to make maintenance much easier Amulet-Team/Amulet-Core#176
• Added in temporary low level entity support (Requires activating with the --experimental-entity-support command line input)

Full Changelog: 0.8.19...0.9.0a1