■World file format changed to format called Anvil.
■World height is now 256 blocks instead of 128 blocks.
■Up to 4096 block IDs can be used.
■Multiplayer light calculations no longer cause affected blocks to be transmitted to the clients, instead the clients will recalculate the light on their own.
■This means that chunk errors can not be fixed by placing a torch anymore
■Villagers will repopulate villages based on how many houses there are available.
■The player may add houses to villages, provided they are enclosed with a roof and wooden door.
■Some nights in villages will be worse than others. Referring to Zombie Invasions
■Added Redstone Lamp.
■Decreased chance for the rare mob drops.
■All animals use the new AI system now.
■Animals can now move their heads when walking.
■Baby animals will now follow wheat.
■Fixed wolf AI (They no longer teleport huge distances when the player is hit).
■Fixed zombies breaking Iron Doors.
Notable Bugs
■On newly generated worlds, lighting is broken. Most areas are always light, unless it's night-time.
■In SMP, powering a Redstone Lamp will not update the lighting.
■Lightning updates cause stuttering.
■Caves don't generate.
■The End does not generate (only a spawn platform and a Dragon).
■As the max world height of the Nether is also increased to 256, but Nether world generation is unchanged, mobs and Mushrooms will spawn on top of the Bedrock ceiling.
■Snow does not show up on maps.
■Pickaxes enchanted with Silk Touch no longer cause glass to drop itself when broken. (bug?)
■Taiga biomes do not spawn trees anymore.
■Swamp biomes spawn very few trees.
■Player can glitch through walls using enderpearls. (Both in SSP and SMP)
■Zombies burn during daytime even if it is raining (when spawned from the egg and in contact with fence).