Redstone Update

The Redstone Update is a planned major update labeled as 1.5. Development began shortly after the announcement at MineCon 2012 at the Future Updates with the Minecraft PC Team and The Future of Mod API talks.

You can watch the presentation here:

So far, nine development snapshots from to  have been released. Mojang has stated that they are starting to wind down from adding new features and are instead focusing on fixing bugs. Mojang is preparing for a potential pre-release of The Redstone Update in a few weeks' time, and it will probably be released in late February 2013.

General

 * Rendering engine rewrite
 * Some rendering optimizations.
 * Requires a higher OpenGL feature-set.
 * Includes some sort of fallback for older hardware.
 * Much faster overall rendering, resulting in more Frames per Second.
 * Lighting will interact correctly for some blocks.
 * New Texture Packs format
 * Textures now use one file per block or item, which are stitched together at runtime, texture sizes don't need to be consistent
 * Textures can be animated.
 * Animation frames are underneath each other in the right  format.
 * Use an optional  to specify frame order and duration.
 * Special rules apply for water, lava, compass, and clock.
 * Vanilla textures will be used if texture files are missing.
 * Support for HD texture packs.

Gameplay

 * Added Scoreboard system
 * Intended for map makers or server administrators.
 * Good for PVP servers.
 * Used via  command or command block.
 * The scoreboard can be used to track deaths, players killing another player, players killing a mob, or players activating commands.
 * The complicated system uses a combination of name, display name, and criteria, and track an integer number of points for players.
 * Have Team mechanics including custom name colors, friendly fire options and objective tracking per team instead of per player.
 * Displays points below players nametags.
 * Better Inventory management
 * Double click items to fill the stack up as much as possible.
 * Drag item stacks around to divide them up over the dragged-over slots.
 * Drag item stacks around with the right mouse button to place one of that stack in each dragged-over slot, if that slot is not occupied already.
 * + double click items in a crafting area to place all items in the inventory.
 * + double click an item stack to move all other item stacks of that kind to that part of the inventory.
 * Pressing while the mouse is over an item in the inventory or a container to drop it
 * Held armor can be equipped by right-clicking.
 * Improved Death Messages
 * Now include the cause of death, the player the deceased player was fighting at time of death and name of the item used to kill.
 * Player fell off a ladder
 * Player fell off some vines
 * Player fell out of the water
 * Player fell from a high place
 * Player fell into a patch of fire
 * Player fell into a patch of cacti
 * Player got finished off by Player or Mob using Weapon
 * Player walked into a fire whilst fighting Player or Mob
 * Player was burnt to a crisp whilst fighting Player or Mob
 * Player tried to swim in lava while trying to escape Player or Mob
 * Player walked into a cactus while trying to escape Player or Mob
 * Player was slain by Player or Mob using Weapon
 * Player was killed trying to hurt Player or Mob
 * Improved Renaming
 * Improved renaming of Spawn Eggs
 * Mobs spawned from renamed eggs have the name of the egg and the names will appear in the death message.
 * Mobs can display their custom name as nametag using an NBT tag.
 * Mobs spawned from named Spawn Eggs display their name over their head when viewed within a 6 block radius.
 * Improved renaming of Containers
 * Renamed Chests, Trapped Chests, Dispensers, Furnaces, Brewing Stands, and Enchantment Tables display the new name in their GUI.
 * Renamed Command Blocks use their name in the chat.
 * Changed Language files updating
 * Language files can now be updated via the background downloader.
 * No need for a new Minecraft release.
 * Options & Title Screen
 * Moved Texture Packs button to options menu, instead of title screen.
 * New Chat Settings in Multiplayer Settings.
 * Scale, Focused Height, Unfocused Height and Width is now configurable.
 * Improved Creative Mode
 * In Creative mode, you can hit mobs or players from five blocks away

Blocks & Items

 * Added Redstone Comparator
 * Based on the idea of the Capacitor
 * The crafting recipe is 3 Redstone Torches, 1 Nether Quartz and 3 Stone
 * It is the same as a repeater, but with 2 inputs
 * If input A is stronger or equal to input B, it either repeats the signal or outputs the difference between A and B, so this can be used to make redstone contraptions like easier Piston Doors.
 * Output is toggleable by right clicking.
 * If input A is weaker than input B, then there is no output.
 * All containers output a redstone signal when a Redstone Comparator is placed against it directly. The strength of it depends on how full the container is and what disc number is used in Jukebox
 * This works with Trapped Chests as well, meaning it can provide two redstone signals with different causes at the same time
 * command can be used in a Command Block next to a Redstone Comparator
 * Added Hopper
 * The crafting recipe is 5 Iron and 1 Chest
 * Places and takes out items in Hoppers, Chests, Furnaces, Minecart with Chests, Minecart with Hoppers, Dispensers, Droppers, and Brewing Stands
 * Allows for the automation of many processes collecting the drops
 * Powering the Hopper now also stops it from taking in items
 * The redstone signal emitted when a Comparator is placed against it directly
 * 1 item will give a signal strength of 1, a third of a stack (21 for items which stack to 64) gives a signal strength of 2
 * The number of full stacks x 3 = Signal strength
 * Added Dropper
 * The crafting recipe is 7 Cobblestones and 1 Redstone
 * Places items in containers in front of them, if there is no container it will dispense the item without using it
 * A dispenser 'shoots' items at you, while a dropper 'throws' items at you
 * Can face all 6 directions, with a different texture when facing up or down
 * Need redstone signal to drop items
 * Added Daylight Sensor
 * The crafting recipe is 3 Wooden Slabs, 3 Nether Quartz and 3 Glass blocks
 * Outputs a signal with a strength corresponding to the intensity of the sun
 * Added Trapped Chest
 * The crafting recipe is 1 Chest, and 1 Tripwire Hook
 * Gives out a signal depending on the amount of players looking inside
 * Large Trapped Chests can be staggered with Large Chests to allow more compact storage
 * Transmit signal downward through one block. This does not apply horizontally
 * Texture is slightly different than a normal chest, with a red stain around the latch
 * Added Weighted Pressure Plate
 * Used to detect item drops
 * Gold(light) version reaches full strength at 60 items
 * Iron(heavy) version reaches full strength at 600 items
 * Linear, so 10 strength signal means twice as many items as a 5 strength signal
 * Added Block of Redstone
 * The crafting recipe is 9 Redstones
 * Stores 9 Redstone
 * Emits constant redstone signal
 * Works as pushable redstone power source
 * Added Nether Quartz
 * Picked up when you break or smelt Nether Quartz Ore
 * Is a crafting ingredient for Daylight Sensors and Redstone Comparators
 * Can be crafted into decorative blocks.
 * Added Nether Brick (item)
 * Obtained by smelting Netherrack
 * Improved Nether Brick
 * The crafting recipe now is 4 Nether Brick (item)
 * Added Nether Quartz Ore
 * Drops 1 Nether Quartz item when mined
 * Can be smelted in a Furnace to obtain Nether Quartz
 * Can be legitimaly obtained by Silk Touch enchantment
 * Drop more when picked up with Fortune enchantment
 * Added Block of Quartz
 * The crafting recipe is 4 Nether Quartzes in a square
 * Decorative block
 * Added Quartz Slab
 * The crafting recipe is 3 Block of Quartz
 * Can be placed upside down same all other slabs
 * Decorative block
 * Added Quartz Stairs
 * The crafting recipe is 6 Block of Quartz in a usual stair recipe
 * Can be placed upside down same all other stairs
 * Updated to corner same all other stairs
 * Added Chiseled Quartz Block
 * The crafting recipe is 2 Quartz Slabs
 * Decorative block
 * Added Pillar Quartz Block
 * The crafting recipe is 2 vertical Block of Quartz
 * Decorative block
 * Pillar Quartz Blocks can be placed sideways, using the side of the block to place similar to sideways Woods
 * Added Activator Rail
 * The crafting recipe is 2 Sticks, 6 Irons and 1 Redstone Torch
 * Used to trigger Minecart with TNT
 * Used to stop item passing on Minecart with Hopper
 * Needs to be powered by redstone
 * Transmits redstone signal to 8 Activator Rails far
 * Improved Detector Rail
 * Redstone Comparators powered by them now give out a signal depending on the fullness of the container on the rail
 * Improved Minecart
 * The possibility of linking minecarts together (driven by furnace minecarts)
 * Added Minecart with TNT
 * The crafting recipe is 1 TNT and 1 Minecart
 * Triggered by Activator Rails
 * Explodes even more violently the faster it goes
 * In Creative mode when left clicked while moving, the Minecart with TNT explodes
 * Doesn't destroy rails and supporting blocks
 * Still blows up redstone materials
 * Added Minecart with Hopper
 * Crafting recipe is a hopper on top of a minecart
 * Can only be emptied by passing over a hopper
 * Can pick up items from containers when it passes over
 * Added Minecart with Spawner entity
 * Only obtainable with world editors
 * Have only the entity not the item
 * Uses the same NBT format as a normal Spawner
 * Retexturized Lava
 * Updated texture
 * Improved Water
 * Creating an infinite water source no longer needs a block underneath, but has to have a water source block.
 * This means you won't ruin rivers or oceans with Buckets
 * Nerfed Bone Meal
 * Now takes crops 2-3 uses as opposed to automatically pushing them to the final growth stage
 * Saplings take 2 bone meal to sprout into a tree
 * Gives off green particles when used
 * For each plant it is different to get the the final growth stage
 * Basically picks a random stage of growth each time.
 * Added and improved Double Slabs
 * is the "Smooth Stone Slab" and will remain so
 * is the "Smooth Sandstone Slab"
 * Improved Dispenser
 * Now equip armor to players that are up to 1 block away
 * Can place and activate TNT
 * Now use Bone Meal on a crop or sapling in front of them
 * Can create fire in front of them with Flint and Steel, which consumes durability
 * They can now face all 6 directions, and use a different texture when facing up or down
 * Removed Locked Chest texture
 * Texture removed from the game
 * Now uses the "Missing Texture" texture
 * Heighted Snow
 * Fully implemented multiple snow heights
 * Drops one snowball for every layer of snow
 * Each level of snow has its own height collision
 * The topmost layer of snow does not have collision, so the player is always slightly sunken in the snow
 * Visually, four layers of snow is the same height as a slab. However, five layers of snow has the same collision height as a slab
 * Crafting recipe is 3 snow blocks in a row to create 6 snow layers
 * For each thin layer of snow crafted, the player loses exactly half the snowballs required to produce it
 * Improved Beacon
 * Increased range
 * 1 layer: 41 blocks diameter (previously 33)
 * 2 layers: 61 blocks (previously 49)
 * 3 layers: 81 blocks (previously 65)
 * 4 layers: 101 blocks (previously 81)
 * Stairs
 * Improved lighting
 * Stairs no longer prevent sprinting

Mobs

 * New Skeleton Al
 * Now shoot from 16 blocks away, instead of 10
 * Scales to difficulty
 * They now shoot faster when their target is closer
 * They shoot players one block away
 * New Zombie Al
 * Scales to difficulty
 * They now alert other Zombies within a radius when they see a player
 * They get more powerful as they lose health
 * When on fire, they can now set players on fire
 * Now become aggressive and come towards you when shot from farther away
 * Improved all Mobs
 * Mobs no longer walk over rails unless they are pursuing the player

World Generation

 * Added Nether Quartz Ore to the Nether
 * Nether Quartz Ore is found in the Nether, there is an average of roughly 69 ores per chunk
 * Improved Abandoned Mineshaft item spawning
 * Now spawn items on Minecart with Chests, instead of Chests

Bug Fixes

 * Fixed 72 bugs (Issue tracker) The following fixes are only for bugs which were present in a previous stable version of Minecraft. For the full list of bug fixes in snapshots see the Development version history.
 * – Pigs constantly jumping, when player control them on half slabs and stairs
 * - Signs light up when mousing over creative inventory slots
 * – Piston extended and retracted at the same time
 * – Visual glitch on retracting piston
 * – Clocked piston arm turns invisible when exiting game/dying/etc.
 * – Powered redstone doesnt update right
 * – Flowing water still drags the player while flying
 * – Z-fighting of iron bars / glass panes with the block below / above
 * – TNT explosion delayed until exiting and re-entering world
 * – You can place Vines into Vines
 * – Leaves replace transparent blocks
 * – Chest glitch that lets them appear as if they are opened while they are not
 * – Achievements lost after update
 * – Arrows Don't land properly
 * – Breeding cows can consume more than one wheat
 * – Dying stacked leather armor duplicates the armor
 * – Spawn Protection not working properly
 * – Map scaling breaks the map sometimes
 * – In the server log, /say commands performed by the server do not appear to the console but do appear to the players.
 * – Graphical Piston Glitch
 * – Water does not form source blocks properly on top of existing source blocks
 * – Clouds have a transparency when you are above/in them but not when you're underneath them.
 * – Command block/Repeater interacting weirdly
 * – /difficulty command doesn't produce any messages
 * – Different timings on pistons in near same environment
 * – Baby mob collision boxes are too large
 * – Levers have random orientation when placed
 * – Infinite rail duplication glitch
 * – Minecart noise gets stuck on long cart rides | Bumping, choppy sound
 * – Ender Egg falling render problems
 * – Hash size breaks redstone
 * – Mob spawners sometimes show up as pig spawners
 * – Map item placed in item frame experiences Z-fighting
 * – Inconsistent pulse length/delay with torch and repeater combination
 * – Minecraft VERY slow to join/update a server, takes LONG time to login (30 seconds/ 1 min)
 * – Suffocation/jittering/stuck when spawning in a newly created world
 * – Boats and minecarts should not be dropped in Creative
 * – Village lamp post floating torches
 * – Rain animation glitches through the ceiling
 * – Powered/activator rail on slope stays powered/activated
 * – Jukebox crashes when breaking with no record inside
 * – Anvils will sometimes hit the edge of a block and break instead of being placed.
 * – Anvil name change cost
 * – Can't Sprint Going Up Stairs
 * – Block "resets" when right clicked with a food item
 * – Wither In Peaceful spawns very glitchy
 * – Inconsistency with pistons pushing items
 * – Armor enchantments (besides Thorns) have no effect on mobs
 * – Tile entity crashing bug
 * – Block breaking resets when the item you're holding changes
 * – Floating minecart tracks when pushed by one-pulse piston
 * – Pistons and other Non-Solid blocks
 * – Issues with name colors in tab list
 * – Dispensers no longer dispense items through blocks in the downward direction.
 * – Powered mechanisms react to change in redstone power level
 * – SpawnPotentials list working incorrectly
 * – Wither skeletons have wrong hitbox
 * – Chat Shown: commands only broken - displays all chats but prevents me from submitting commands with "cannot send chat message"
 * – Minecart does not make sounds when riding it
 * – Mining with tools resets cracking action when damage values are updated
 * – Blocks like Redstone dust, Repeaters, Doors, Levers do not drop when the underlying block is pushed by a piston
 * – 1.4.6 - Windows 8 64x - Mouse: View issues/Accuracy error?
 * – Crash upon reloading texture pack.
 * – Reading Bytes in Minecraft code has a possible flaw
 * – Trapdoor is closed when redstone repeater is one block below and powered.
 * – ID 73 & 74 Preset Bug
 * – URL parser does not detect 4 letter TLDs
 * – Wither doesn't generate health when in minecart
 * – Gamerule doMobLoot doesn't affect xp drops
 * – Death messages not translatable
 * – FallingSand support for block IDs > 128
 * Confirmed 1 bug fix
 * – Black Lighting