Bukkit

2.1.1:

• Resolved an issue where bukkit specific configuration settings were not being generated
  

2.1:

• Full engine rewrite to fix bugs involving chest, and other blocks.
  
• New configuration backend
  
• Configurable search radius
  
• Configurable trap trigger and return delay
  
• New generic type based abstracted API
  
• More consistent block searching
  
• More reliable block restoration
  
• Ability to make large columns fall instead of just the block immediately above the clay (configurable, off by default).
  

• Frequent server crashes could lead to block loss. Though this shouldn't be a major concern.