Bukkit

Version 1.2

• use bukkit scheduler to prevent threading issues/crashes
• fixed some issues in combination with shopkeepers plugin
• updates for compatibility with 1.4.5
• some slight improvements handling offer creations and removals

Up to Version 1.0.1

• 8/5/12: Initial upload
• 8/20/12: Added many new configuration options, including full config of offers which villagers generate, and compatibility with Shopkeepers.
• 8/20/12: Some minor fixes to warnings and clarification on config.

See here for a complete changelog.

If you have this plugin, Shopkeepers, and a third plugin which can create villagers (VoxelSniper is an example), consider looking into the config.yml's section on Shopkeepers. If you configure these numbers to be too low, and use the third plugin to spawn a villager while your server is badly lagging, a crash may occur.

Two vanilla bugs you may run into (not related to this plugin but still good to know):
https://mojang.atlassian.net/browse/MC-1580
https://mojang.atlassian.net/browse/MC-4134