Bukkit

- Added support for multiple versions of Minecraft. A folder will be created in plugins/WorldEdit/nmsblocks which contains different class files which will be dynamically checked for compatibility with the current minecraft version.

- Added -d flags to //count and //distr, which allow separating blocks by data values.

- Added a butcher brush (//brush butcher) which works like the command in a brush. The flags for the command can be passed an an argument for the brush.

- Fixed an issue with use-inventory where container blocks will spill when being removed.

- Added a setting to allow creative mode players to override use-inventory.

Quote from the WorldEdit team:

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• When possible, update to the latest version of CraftBukkit.
• If you use WorldGuard, be sure to update that too.
• Known issues (updated live): http://youtrack.sk89q.com/issues/WORLDEDIT?q=%23Bug+Affected+versions%3A+5.5.1