1.6:

New features:
+ Added Nether support to multiplayer
+ The client will ask minecraft.net if the current login is valid. If the server says “no”, a warning message appears in the client. You can still play the game even if this happens.
+ Added craftable maps
+ Added hatches
+ Added tall grass in some biomes
+ Mushrooms now spreads (very) slowly
+ Added server property view-distance. Sets the radius of terrain updates (in chunks) to send to the players. Range 3-15, default 10.
+ Added dead shrubs in deserts
+ Added allow-nether (set to true or false) in server.properties
+ Blocks destroyed by other players in multiplayer now shows the breaking block particle effect
+ Doors make sound for other players in multiplayer
+ The record player now supports more than 15 different songs (you can’t get the records yet, though)
+ Activated dispensers make sounds and trigger particles in multiplayer
+ Players stuck in walls will slide towards the nearest gap if there is one

Changes:
* Disabled Advanced OpenGL until we can fix some bugs with it
* It’s no longer possible to build solid blocks on the top layer of the maps (sorry!)
* Made booster tracks speedier
* Severely nerfed fire so it spread slower, and doesn’t spread infinitely
* Seeds are now found in tall grass, using a hoe on the ground no longer works
* Compressed network traffic more agressively
* Blocks that don’t change appearance when the data changes don’t send block updates when their data changes now
* Arrows shot by players can now be picked up by all players
* Nothing riding anything or being ridden by anything can enter portals

* Fixed running out of memory corrupting the current level
* Fixed the side textures of grass getting extra dark when mining them
* Fixed anaglyph 3d rendering mode having severe visual bugs
* Fixed the crash screen vanishing immediately
* Fixed not being able to target blocks when at x or z pos 1000
* Fixed the achievements screen messing up the sky color
* Fixed saving while sneaking dropping the player through the ground
* Fixed a system clock change messing up the game speed
* Fixed rain sounds not playing with fast graphics enabled
* Fixed hair and cloaks being rendered in the wrong locations on sneaking players
* Fixed the attack/swing animation not being applied to the armor layer
* Fixed player rotation not being loaded correctly when loading a saved game
* Fixed arrow physics, making them not get stuck midair when you open a door
* Fixed arrows hitting reeds, portals, and other non-solid blocks
* Fixed keybindings not getting saved properly under certain conditions
* Fixed the player not being able to sneak off lowered blocks like cacti
* Fixed a bug where the player could mine without swinging their arm
* Fixed boats placed on snow being placed too far up
* Fixed submerged boats rising very very fast
* Fixed sand dropping onto boats getting stuck in a falling animation
* Fixed a game crash when riding a vehicle or animal into the nether
* Fixed falling while riding not dealing damage to the rider
* Fixed buttons and levers too close to the player being impossible to use
* Fixed dispensers shooting through walls
* Fixed fire hurting through wall corners
* Fixed entities reaching water through wall corners
* Fixed placing doors next to cacti creating half-doors
* Fixed buttons and levers being placeable on leaves in “fast graphics” mode
* Fixed furnaces and dispensers not dropping their contents when destroyed
* Fixed dispensers biasing later slots
* Fixed farmland taking too long to dig
* Fixed tilling below some blocks being possible
* Fixed tilling the underside of blocks somehow working
* Fixed fences and stairs sometimes becoming invisible
* Fixed walking on top of fences not producing step sounds
* Fixed fire sometimes existing mid-air as an invisible block of pain
* Fixed fences and wooden stairs not being flammable
* Fixed fire effect on burning entities sometimes getting rendered in the wrong location
* Fixed fishing rod rendering being a bit lacking
* Fixed fishing rods being stackable
* Fixed mining glass hiding the clouds behind the glass
* Fixed rain falling through liquids
* Fixed items in glass blocks not getting ejected properly
* Fixed water interacting strangely with glass
* Fixed glass not blocking rain sound
* Fixed fences and signs preventing grass from growing
* Fixed rain and snow being incorrectly lit
* Fixed grass staying alive below stair blocks
* Fixed the achievement screen not pausing the game
* Fixed some screens breaking the sky tint color
* Fixed fullscreen mode switching causing mouse issues and screen closes
* Fixed chat messages surviving through game switches
* Fixed ice so it regenerates regardless of whether it’s snowing or not
* Fixed rain falling too slowly
* Fixed levers being placeable on weird locations
* Fixed floor levers sometimes not delivering a signal downwards
* Fixed floor levers sometimes not being removed when the floor is removed
* Fixed rail tiles sometimes not properly connecting to a new neighbor
* Fixed minecarts next to each other causing extreme velocities (sorry!)
* Fixed wolves not following their owner if the name has different caps
* Fixed creepers retaining charge level when they can’t see their target
* Fixed dying in the nether spawning new portals
* “Fixed” beds in the nether
* Fixed inventory acting weird when portaling by making the portal close all screens
* Fixed wooden pressure plates being mined with pickaxes
* Fixed redstone repeaters having the wrong particles
* Fixed saplings being plantable through snow onto non-grass blocks
* Fixed ore density varying per quadrant from the center of the world
* Fixed dispenser graphics being one pixel off. ONE PIXEL!!!
* Fixed mushrooms spawning everywhere during nights
* Fixed animals only spawning near light during the night
* Fixed the multiplayer join screen input field being too short
* Fixed IPv6 addresses being parsed wrongly. To connect to a specific port in IPv6, use the format [1234:567::1]:25565
* Fixed network packets being sent unbuffered, causing huge amounts of packets being sent
* Fixed entity positions going out of synch sometimes. They get re-synched every 20 seconds now.
* Fixed inventory icons not animating after being picked up in multiplayer
* Fixed mushroom soup not leaving a bowl in multiplayer
* Fixed entities above the map height limit becoming invisible
* Fixed healing not flashing the health bar in multiplayer
* Fixed arrows being animated really strangely in multiplayer
* Fixed arrows triggering too many entity move updates in multiplayer
* Fixed the compass not pointing at the spawn location in multiplayer
* Fixed fires being impossible to put out in multiplayer
* Fixed record players spawning client-side fake records in multiplayer
* Fixed records not playing for other players in multiplayer
* Fixed players spawning in the wrong location and quickly lerping to the correct location
* Fixed monsters not being visible for players with their difficulty set to peaceful
* Fixed pigs getting hit by lightning in multiplayer spawning client-side zombie pigmen
* Fixed loads of exploding tnt generating way too many particles, possibly crashing the client
* Fixed bonemeal use in multiplayer sometimes spawning fake client-side trees
* Fixed saplings sometimes spawning trees client-side in multiplayer
* Fixed weather sometimes changing client-side in multiplayer
* Fixed grasscolor.png and foliagecolor.png not being read from texture packs
* Fixed stats getting saved to different files in offline mode if the caps in the player name differ from the true spelling
* Fixed fireballs not being visible in multiplayer
* Fixed ghasts’ fireing animation not being visible in multiplayer
* Fixed receiving more items than the maximum stack size sometimes causing an oversized stack in the inventory