Fixed a crashed caused when a mod tries to check if a creature is hostile or not from the client when the creature isn't fully initialized and spawned in the world.
Fixed the Custom potion Effects ID disabling and if a bad effect is applied, it will be removed from the entity, also any bad potion effects saved to a world (entity NBT) will be removed when loading, this should stop all problems all together and will fix worlds broken by this bug.
Added a Custom Potion Effects Setup debug option, this will print out extra info about custom effects.
For Minecraft 1.6.4: Hotfix 1.5.1d has been release with this fix too!
Major Bug Fix: Fixed console spam! The network code has been redone a bit and shouldn't cause any more problems now!
Change: Friendly Fire has been improved, pets can no longer harm other pets/minions, etc. Also pets shouldn't be able to harm players if PvP is disabled.
Bug Fix: Aggressive targeting should avoid animals