Bukkit

• Improves MythicMobs integration
• Adds custom blocks
• Adds custom food
• Adds custom guns
• Adds integration with ActionBarAPI for custom tool durability and wand/gun indicators. See https://knokko.github.io/custom items/compatibility/positive.html
• Adds firework projectile effects
• Adds push/pull projectile effects
• Adds sound projectile effects
• Adds potion aura projectile effects
• Adds launch knockback and impact knockback to custom projectiles
• Adds custom crossbows
• Minor improvements to the custom crafting implementation
• Fixes a bug regarding custom tools that are repaired using an anvil
• Adds amounts and remaining items to the ingredients of crafting recipes, container recipes, and to anvil repair items
• Improves the performance of custom containers
• Adds pocket containers
• Fixes critical bugs in non-persistent custom containers
• Adds storage slots to custom containers
• Minor implements to the item update process

This version is marked as beta because it adds a lot of new features and is not very well tested.