1.4 is working but currently testing and adding features
Wasn't too bad getting 1.4 working but currently adding some features before a release and its needs an extensive testing as well. Ropes and chains are in though and are setup so if you are jumping while on them you go up. If you hold shift on them then you stop moving.
Items before I release the 1.4 patch
Add wolves to mob spawner
Refix slimes so they don't split (slime code changed with 1.4)