Java Edition guides/Redstone Update

This guide is a simplified overview of all the changes in the Redstone Update ( 1.5.x releases), which assumes at least some familiarity with the Pretty Scary Update (Java Edition 1.4.x releases).
== Mobs ==
=== Changed ===
All mobs 		
* Mobs no longer walk over rails unless they are pursuing the player
Skeletons		
* Now shoot from 15 blocks away, instead of 10
* Now shoot faster when their target is close, depending on difficulty
Slimes 		
* Slime spawn rates in swamps now depend on the current moon phase
Zombies 		
* Now group up on targets
* They can now set players on fire when on fire themselves
* Increased zombies attack damage
* Increased player detection range
== Blocks ==
=== New ===
Activator Rail 			Pickaxe 	
* Triggers players, if rail is powered. 
* Can be used to explode TNT Minecart.
Block of Redstone 			Pickaxe 	
* Acts as a redstone power source
Daylight Sensor 			Any 	
* Produces redstone power only during the day.
Dropper 			Pickaxe 	
* Item transport
Hopper 			Pickaxe 	
* Can be used to transfer items without the danger of them despawning
Redstone Comparator 			Any 	
* Compares redstone signals
Trapped Chest 			Axe 	
* Can be used for traps
Weighted pressure plate			Pickaxe 	
* More items on pressure plate increases the redstone signal.
** Full signal strength is reached at 60 items
** Full signal strength is reached at 600 items
Nether Quartz Ore 		
* Generates in any Nether biome.	Pickaxe (Drops Nether Quartz unless Silk Touch is used)	
* Drops nether quartz when mined.
Block of Quartz 			Pickaxe 	
* Can be used as a decorative block
Quartz Pillar 			Pickaxe 	
* Can be used as a decorative block
Chiseled Quartz Block 			Pickaxe 	
* Can be used as a decorative block
Quartz Slabs and Stairs			Pickaxe 	
* Can be used as decorative blocks
=== Changed ===
Beacon 		
* Increased effect radius from 16/24/32/40 blocks to 20/30/40/50 blocks
Brewing Stand, Chest, Detector Rail and Jukebox		
* Now emit a redstone signal into an adjacent comparator. Signal strength depends on the fullness of the block
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
* No longer fire while updated, instead they fire when their input becomes powered
* Now emits a redstone signal into an adjacent comparator. Signal strength depends on the fullness of the dispenser
Lava 		
* Flows faster in the Nether
* Updated texture
Nether Bricks 		
* Now has a crafting recipe of 4 Nether Brick items.
== Items ==
=== New ===
Nether Brick (item)			
* Can be used to make nether brick blocks.
Nether quartz 		
* Is now dropped from nether quartz ore	
* Is a crafting ingredient for daylight sensors and redstone comparators.
* Can be crafted into building blocks.
=== Changed ===
Bone Meal		
* Now picks a random stage of growth each time, as opposed to automatically pushing them to the final growth stage
* Saplings take 2–4 bone meal to sprout into a tree
* Gives off green particles when used
== Non-mob entities ==
=== New ===
Minecart with hopper 				
* Can only be emptied by passing over a hopper
* Can pick up items from containers when it passes under them
Minecart with TNT 				
* Gets triggered by activator rails
* Explodes more violently the faster it goes
* Doesn't destroy rails, supporting blocks or redstone materials
Minecart with Spawner		
*Can only be spawned in through commands.		
* Functions the same as a spawner, but can move like a minecart.
== Structures ==
=== Changed ===
Mineshaft		
* Now generates loot in minecarts with chests, instead of chests
== Enchantments ==
=== Changed ===
Fortune 	
*Now affects apples and potatoes.
Efficiency	
*Tools enchanted with efficiency now only speed up the mining of blocks that the tool is intended for.
es:Guías de Java Edition/Redstone Update‏‎
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ru:Руководства по Java Edition/Redstone Update
zh:Java版指南/红石更新