Notes

Added Basalt Deltas biome to the Nether
Added Crimson Forest biome to the Nether
Added Hoglins
Added Netherite
Added Piglins
Added ruined portals
Added Soulsand Valley biome to the Nether
Added Striders
Added Warped Forest biome to the Nether
Added Zoglins
Added a new disableChat command line option – when used, receiving and sending online chat is disabled
Added a new disableMultiplayer command line option – when used, the Multiplayer button is disabled
Added bastion remnants
Added new Game Mode Switcher debug menu
Added new Nether blocks
Added the Soul Speed enchantment
Added the lodestone
Added the respawn anchor that allows you to set your respawn point in the Nether. Use while holding glowstone to charge to a maximum of four charges – each respawn use one charge
You can charge the respawn anchor using a dispenser
Added the target block
Basalt is formed when lava flows over soul soil next to blue ice
Bell blocks will now ring when hit by any projectile
Bells can now be hung from the underside of more blocks
Compasses can now be enchanted with Curse of Vanishing
Endermen can now pick up some of the new Nether blocks
Endermen will no longer pick up Netherrack
Entities now get pushed by flowing lava
Farmer Villagers can now compost seeds
Fish now despawn when further than 64 blocks away from the closest player
Huge fungi will now only grow on its matching type of nylium
Knockback resistance is now a scale instead of a probability
Lily pads are now considered junk fishing loot rather than treasure
Patrols no longer spawn when the player is close to a village
TNT and campfires will now ignite when hit by any burning projectile
The General statistics list is now alphabetically sorted
Updated logos for Mojang Studios and Minecraft
Villagers can now spawn iron golems regardless of their profession status or latest working time
Walls do not have gaps anymore when stacked vertically
Walls will now connect to even more things, such as iron bars, panes, pressure plates, banners, and even pickles
When a Villager is struck by lightning, the witch it is converted to will no longer despawn
When fishing, treasure loot can now only be obtained by fishing in open waters
Accessibility

Added "Line Spacing" chat and accessibility option
Added "Chat Delay" accessibility option
Advancements

Piglins and Hoglins are now required for Monster Hunter and Monsters Hunted
Serious Dedication is now awarded for obtaining a Netherite hoe
Obtaining blackstone now also counts for the Stone Age advancement
Breeding Striders now counts for The Parrots and the Bats and is now required for Two by Two
New Advancements

Bullseye unlocks when hitting the bullseye of a target block from at least 30 meters away
Hidden in the Depths unlocks when obtaining ancient debris
Cover Me in Debris unlocks when obtaining full Netherite armor
Country Lode, Take Me Home unlocks when using a compass on a lodestone
Who Is Cutting Onions? unlocks when obtaining crying obsidian
Not Quite "Nine" Lives unlocks when setting a respawn anchor to the maximum
This Boat Has Legs unlocks when riding a Strider with a fungus on a stick
Hot Tourist Destinations unlocks when visiting all biomes in the Nether
Those Were the Days unlocks when entering a bastion
War Pigs unlocks when looting a chest in a bastion
Oh Shiny unlocks when distracting an angry Piglin with gold
Basalt Deltas

Basalt Deltas can now be found in the Nether!

Remnants of volcanic eruptions, this biome sports a high concentration of basalt columns and lava deltas
Walking through it, you will be surrounded by flowing flakes of white ash
Magma cubes finally have their own home and spawn very frequently here
A new block, blackstone, can be found here in large patches
Bastion Remnants

What's made of blackstone and full of Piglins and Hoglins? Bastion remnants!

Added four separate bastion remnant types: bridge, Hoglin stable, housing units, and treasure room
You can find these sizable structures in all Nether biomes, except the treacherous ash-dusted regions of Basalt Deltas
Explore, loot, and conquer a bastion remnant to call it your home – but beware! Piglins don't take kindly to intruders stealing their possessions
Bees

Reduced the maximum distance a bee can wander away from its home hive to ~22 blocks
Block Renames

Some blocks have been renamed. Turns out singular fungus in the Nether attempted to falsely present itself as many fungi – so sneaky!

Crimson fungi is now called crimson fungus
Warped fungi is now called warped fungus
Blocks

Many new blocks have been added, and changes have been made to a few existing ones.

Added crying obsidian. It's sad and cries purple energy
Added basalt. Craft it 2x2 or use a stone cutter to create clean and shiny polished basalt!
Added blackstone, along with its variants: regular, polished, and polished brick
Blackstone can be used to craft furnaces and stone tools
Added gilded blackstone – blackstone which has been imbued with gold and has a chance of dropping gold nuggets when broken
Added chiseled Nether bricks, cracked Nether bricks, and quartz bricks!
Added two new non-flammable wood-like blocks: crimson stems and warped stems
Added crimson and warped hyphae – all-sided "stem" blocks, including stripped variations
Added new ground surface blocks: crimson nylium and warped nylium
Added new vegetation: Nether sprouts, crimson roots, and warped roots
Added two types of fungi: crimson and warped. Try using bone meal to grow them!
You can place crimson and warped roots and fungi into pots
Added warped wart blocks
Added weeping vines that grow from the bottom of a block downwards
Added twisting vines that grow upwards
Added a new natural light source block: Shroomlights
Added soul soil. Whenever fire burns on soul soil, it burns with a blue flame
Soul soil and soul sand can be used to craft soul torches, which in turn can be crafted into soul lanterns
The Wither can now be summoned using soul soil as base
Added soul campfires. Warm your buns with the heat of one thousand souls!
Added chain blocks
Nether gold ore can now be found in the Nether – it drops a few gold nuggets and can be mined with any type of pickaxe
Bone meal can now be used to grow kelp, weeping vines, and twisting vines
Using bone meal on Netherrack can now spread nylium
Nether vegetation blocks (sprouts, roots, vines, fungus, wart and wart blocks) are now compostable
Nether sprouts can be harvested with shears
Food can now be placed on unlit campfires
Creative Mode

You can now milk cows and Mooshrooms in creative mode
You can now get stew from Mooshrooms in creative mode
When using an empty bucket on water in creative mode, you now get a bucket of water. If you have a bucket of water in your inventory already, no additional water buckets will be added when you use your empty bucket on water
Crimson Forest

Crimson Forests can now be found in the Nether!

Crimson nylium carpets the cave floor with all kinds of strange new vegetation
Crimson nylium can be bonemealed to get more of this strange new vegetation
Huge crimson fungi make up the "trees" of this forest, with Shroomlights lighting up the forest floor
Nether wart blocks can be cleared quickly using a hoe
Weeping Vines grow from the cave ceilings and fungi
Hoglins wander these forests
Crimson spores swirl through the air
Dispensers

Dispensers can now saddle pigs and horses
Dispensers can now put horse armor on horses
Dispensers can now put carpets on llamas
Dispensers can now put chests on llamas, donkeys and mules
Dispensers can now shear a Mooshroom
Dispensers can now shear snow golems
F3 + N (Toggle Spectator)

A small change has been made to this debug combination.

By default, using this key would return you to Creative after toggling from Spectator. It now will toggle back to the previous game mode you had
As an example, if you were in Survival, then toggled to Spectator and back, you would be set back to Survival
Farmers

Farmers can now put excess seeds in the composter to create bone meal
Bone meal is used by the farmers to grow crops
Farmers share excess wheat to other farmers, so more farmers can make bread
Game Mode Switcher

New F3 debug feature which allows you to switch game modes with traditional "tabbing" functionality.

Hold F3 and tap F4 to open the menu
Tapping F4 will cycle the game mode, or you can use the mouse
Release F3 to apply
Your last game mode is remembered and will be the first selected option, so you can quickly toggle between two game modes with a single press of F3 + F4!
Hoe Changes

We've made some changes to hoes to make them more useful in the Nether.

Each tier has different speed at which hoes mine blocks they are effective against
Hoes can now be enchanted with the following enchantments: Efficiency, Fortune, Silk Touch
Those enchantments can now be provided through enchanting table
Hoes are now the appropriate tool for mining hay, targets, dried kelp blocks, leaves, Shroomlights, Nether wart blocks, warped wart blocks, sponges, and wet sponges.
Hoglins

Hoglins are big aggressive beasts that live in crimson forests in the Nether
They attack players on sight. Be careful – they can easily knock you off a ledge!
Hoglins drop pork and sometimes leather, but not willingly
You can breed Hoglins by feeding them crimson fungi. Do so at your own risk
Hoglins get hunted by Piglins sometimes, but they don't go down without a fight
Despite this, Hoglins and Piglins aren't enemies – more like an ecosystem
Baby Hoglins like to pretend they are tough – but don't worry, they're more bark than bite
Want to keep hoglins off your back? Pro tip: Hoglins hate the smell of warped fungi
Hoglins that somehow end up in the Overworld become Zoglins fairly quickly – but who would ever bring a Hoglin to the Overworld?
Lodestone

A new block that can help you get your bearings!

Crafted from a Netherite ingot and chiseled stone bricks
Use a compass on a lodestone to create a lodestone compass, which will point to that lodestone
Mobs

Players can no longer mount another entity when the crouch key is held down
Added gamerule universalAnger (disabled by default), which makes angered neutral mobs attack any nearby player – not just the player that angered them. Works best if you disable forgiveDeadPlayers
Added gamerule forgiveDeadPlayers (enabled by default), which makes angered neutral mobs stop being angry when the targeted player dies nearby
Forgive dead players

If this gamerule is disabled, then angered mobs will stay angry even if the targeted player dies
If both forgiveDeadPlayers and universalAnger are enabled, an angered neutral mob will stop being angry when their target dies. They won't seek any new targets after that
Notable exception: Angered Zombified Piglins continuously spread anger. So even if one Zombified Piglin stops being angry because its target died, other angered Zombified Piglins nearby are likely to make it angry again. The only way to stop the anger is if none of the angered Zombified Piglins see a player for a while
Neutral mob anger

Updated anger management for most neutral mobs (polar bear, wolf, bee, Enderman, Piglin, Zombified Piglin).

When hurt by a player, the neutral mob will target that player and try to kill it
The mob will stay angry until the player is dead or out of sight for a while
Anger is persistent, so a player can't escape by temporarily logging out or switching dimension
If a targeted player dies near the angered mob, it will stop being angry (unless forgiveDeadPlayers is disabled)
Neutral mobs also get angry at other mobs who hurt them. However, that anger is not persistent
Angered neutral mobs will only attack the offending player, not innocent bystanders
Notable exception: If a beehive or nest is broken, the bees will be angry at all nearby players
Some mobs spread anger (wolf, Zombified Piglin, Piglin, bee). If a player attacks one, all nearby mobs of the same type will get angry at that player
Universal anger

Universal anger is basically guilt by association. A neutral mob attacked by players will be angry at players in general, regardless of who attacked them. More specifically:

A neutral mob attacked by a player will target the nearest player, even if that player wasn't the attacker
Every time the neutral mob is hit by a player it will update its attack target to the nearest player
Players can use this to make neutral mobs attack other players. Who would ever do something that devious?
Universal anger does not apply when a neutral mob is attacked by another mob - only when it is attacked by a player
Universal anger is persistent. The angered mob will stay angry even if the player logs out and logs in, or jumps through a portal and back
Mobs that spread anger will also spread universal anger. So if a player attacks a Zombified Piglin, all other Zombified Piglins within sight will be universally angry and attack their nearest player
An angered neutral mob will stop being angry if it can't see any eligible target for a while
Zombified Piglins

Zombie Pigmen are now known as Zombified Piglins, and they now have ears. Well, at least one ear
Zombified Piglins no longer attack innocent bystanders (unless you enable gamerule universalAnger)
Zombified Piglins stop being angry if the targeted player dies nearby (unless you disable gamerule forgiveDeadPlayers)
Zombified Piglins continuously spread to other Zombified Piglins, as long as they see their target
Nether Biome Fog

Biome fog color smoothly blends between biomes. Smooth!
Netherite

A new high level material found in the Nether. Use it to upgrade your diamond gear!
How to make Netherite

Mine ancient debris in the lower depths of the Nether. At your own risk though. No insurance coverage for that
Refine it into Netherite scrap in a furnace or blast furnace
Combine four Netherite scrap with four gold ingots in a crafting table to make a Netherite ingot
Use a smithing table to fuse the Netherite ingot with your diamond weapon, tool, or armor
Netherite effects

Netherite items float in lava – just so you don't lose all your gear after that unplanned lava bath
Netherite items have higher enchantment value than diamond (but not as high as gold)
Netherite tools work faster and last longer than diamond
Netherite weapons do more damage than diamond
Netherite armor have higher toughness and durability than diamond
Netherite armor gives you knockback resistance, so you barely get knocked back at all when hit by arrows and such
Netherite blocks can be used as the base of a beacon and Netherite ingots can be used as the fuel for a beacon. Weird flex but ok
...and it looks cool!
Parity

Changed ambient block lighting in the Nether for parity with Bedrock edition
Parrot

Parrots imitate hostile mobs less often
Parrots do not randomly imitate hostile mobs when gamemode is on peaceful
Piglins

Piglins are an aggressive civilization that live in the Nether
They mostly hang around in Crimson Forests, but you might find some in the Nether Wastes too
They think of players as target practice and will attack on sight
However, if you dress appropriately, they will see you as a respectable figure. Or tolerable at least
Piglins are suspicious of strangers. If they see you opening a chest or other container, they will assume that you're stealing and will treat you accordingly
If Piglins hear you break a chest or a block of gold (or similar), they will also assume you are stealing
Piglins LOVE gold and get very distracted by gold items
Gold ingots are currency to Piglins. Throw ingots at them, or right-click them with an ingot, to barter for various goods
Piglins sometimes get hungry and hunt Hoglins for food. Or they try at least. They results... vary.
Piglins prefer to hunt and fight in groups. When a fight is happening, everyone wants in
Piglins that somehow end up in the Overworld become zombified fairly quickly
Piglins are creeped out by soul fire and Zombified Piglins, and will avoid them if possible
Wither skeletons and Withers are a historic enemies of the Piglins and will be attacked on sight
Baby Piglins are not as dangerous, but they can be mischievous, so watch your back
...and they like to play with Baby Hoglins
Added a Piglin banner pattern that can be found in bastion remnants
Redstonewire

The blockstate, rendering, and behavior of redstone wire are more in line with each other. Redstone will provide power to blocks on all sides it shows a visual connection to, and not do so on those sides without a visual connection.

A dot of redstone will not power its surrounding blocks
A single redstone wire is now represented as a cross
A wire on top of a block, which is redirected from below, will now power the sides it is redirected to. E.g. a fence gate above the redirecting wire will be powered
Wires that redirect upwards to wires on non-conductive blocks used to only be redirected visually. Now, this redirection applies to their behavior as well
A wire that is redirected to go over a block will now always provide power to the block. This is most noticeable when the wire has signal strength 1
When right-clicking a single piece of redstone, it will toggle between a the cross and the dot
Target block

The target block now conducts redstone signals
Ruined Portals

Shattered remains of ancient Nether portals. Wonder who built them?

They can be found in any Overworld or Nether biome
Some are hidden underground, under the sea, or buried in sand
Soul Speed

Never suffer again drudging through Soul Sand Valleys – Soul Speed has you covered!

Shine your boots of choice with this soul-sucking enchantment to speed around on soul sand and soul soil
However, there's a downside: enchantments will slowly degrade your boots each soul block you walk on
Can only be obtained by bartering with those pesky Piglins
Soulsand Valley

Soulsand Valleys can now be found in the Nether!

An open space made mostly of soul sand and soul soil
Basalt pillars span from floor to ceiling
Fossile remains of unknown creatures from the past litter the valley
Ash falls through the air
A light blue glow envelopes the valley
Beware of skeletons here
Sounds

Ghasts sounds are now heard at shorter range
Updated block sounds for bone blocks, Netherrack, soul sand, Nether wart, Nether bricks, and quartz ore
New ambient sounds for the Nether biomes
New mood detection algorithm for cave sounds
Added a new music disc titled "Pigstep" by Lena Raine, which can only be found in bastion remnants
Strider

A new mob living the lava lakes of the Nether.

Strides on top of the surface of lava
Can be saddled, but has a will of its own
Really likes the smell of warped fungi – might even be convinced to follow it
Target Block

Because let's face it, your aim could use some practice!

The closer you hit to the center, the larger the redstone signal
Test your skills with a variety of projectiles, including eggs, snowballs, tridents, and more
You will need one hay block and four redstone for this recipe
Villager Workstation Logic

Villagers no longer try to work at the same workstation
The most experienced nearby villager for the profession corresponding to the workstation you add will get the workstation
Villagers now have to walk to and reach the workstation before they can acquire the profession and/or work there
Villagers can no longer claim workstations or professions during raids or night time
Villagers will check and make sure their workstation is valid at all times of day as long as they are within 16 blocks of their workstation
Warped Forest

Warped Forests can now be found in the Nether!

Warped nylium carpets the cave floor with all kinds of strange new vegetation
Warped nylium can be bonemealed to get more of the strange new vegetation
Huge warped fungi make up the "trees" of this forest, with Shroomlights lighting up the forest floor
Warped wart blocks can be cleared quickly using a hoe
A dark blue fog covers the forest
Warped spores swirl through the air
The Warped Forests are strange, but also the least hostile place in the Nether
Weeping Vines

Weeping vines are now climbable!
World Generation

The old Nether biome is now called Nether Wastes
Shipwrecks and ocean ruins are now a bit less common, so you get more excited when you find one!
Patches of blackstone and gravel now generate in all Nether biomes, and patches of soul sand now generate in Soul Sand Valleys
Zoglins

Zoglins are zombified Hoglins – the result of bringing a Hoglin into the Overworld
Unlike Hoglins, they can't be bred or fed, and they don't care about warped fungus
Beware – these beasts are raving mad and attack just about everything they see!
Technical

Added target_hit advancement trigger
Added thrown_item_picked_up_by_entity advancement trigger
Added player_generates_container_loot advancement trigger
Added item_used_on_block advancement trigger
Removed safely_harvest_honey advancement trigger
Added player check to every trigger (except impossible)
Entity checks in triggers can now use loot table condition syntax
Attributes are now added to game registry, similar to items, sound events, etc.
Chat component style can now select font.
Block storage format in chunks slightly changed to speed up various tasks (rendering, pathfinding, world generation, etc).
Added a locatebiome command
Tab completion for resource location will match any part after an _
The compass now has LodestonePos, LodestoneDimension and LodestoneTracked data fields. If LodestoneTracked is zero, the game will skip checking for a Lodestone in the specified position
Slightly changed datapack loading to prevent custom datapacks from crashing
Data packs can now be selected on world creation
Added a enable-status option to the server.properties file which if set to false will suppress replies to status requests from clients. This makes the server appear offline in the multiplayer screen
Full range of Unicode characters is now supported (some may know what that means 😉)
Mobs avoid walking on magma blocks and lit campfires
Cached repeated block type lookups and collisions during pathfinding for increased performance
Minor optimizations in collision detection
Top level element in predicate file can now be array (all contents will be ANDed)
Smithing recipes can now be added or changed through data packs
Added control over how much entity data a server sends to clients
Added a JMX MBean to monitor dedicated server tick times
Shulkers with "NoAI" can now be summoned with rotation
Added strider_one_cm custom statistics for riding Striders
Expanded the max size per axis of structure blocks from 32 to 48
Region files are now opened in synchronous mode to increase reliability
Difficulty and game rules can now be changed from "Create World" screen
"Singleplayer" button will jump directly to "Create World" screen if there are no worlds to select
Temporarily removed structure settings from flat level preset strings (workaround: use import/export settings functionality)
Advancements

Extended entity checks

Entity checks in triggers can now use loot table condition syntax. Old notation:

{
"trigger": "minecraft:player_killed_entity",
"conditions": {
"entity": {
"type": "minecraft:blaze"
}
}
}
is now equivalent to:

{
"trigger": "minecraft:player_killed_entity",
"conditions": {
"entity": [
{
"condition": "minecraft:entity_properties",
"predicate": {
"type": "minecraft:blaze"
},
"entity": "this"
}
]
}
}
Note 1: Like in loot tables, all conditions in top level array must be met for whole condition to trigger. Note 2: To access new functionality, top level element must be JSON array. JSON object are interpreted as old notation.
Full list of extended triggers:

New field player in every trigger
bred_animals - parent, partner, child
channeled_lightning - victims
cured_zombie_villager - zombie, villager
fishing_rod_hooked - entity
killed_by_crossbow - victims
player_killed_entity - entity
entity_killed_player - entity
player_hurt_entity - entity
summoned_entity - entity
tame_animal - entity
target_hit - projectile
villager_trade - villager
Miscellaneous trigger changes

Due to addition of player, existing contents of location, slept_in_bed, hero_of_the_village, voluntary_exile can now be placed in location field instead of top-level object. Old syntax is still supported, but depreciated.
location got a new property smokey which checks if the location is closely above a campfire
entity_properties got new properties vehicle and targetedEntity which match the vehicle or the entity targeted by a mob
New trigger

target_hit trigger type
signal_strength matches the signal strength output from the block on hit
projectile matches the projectile entity
shooter matches the player who shot or threw the projectile
item_used_on_block trigger type
item matches the thrown item which was picked up
entity matches the entity which picked up the item
player_generates_container_loot trigger type
loot_table matches the resource location of the generated loot table
item_used_on_block trigger type
location matches the location at the center of the block the item was used on
item matches the item used on the block
Attributes

Attributes have been moved to game registry. That means few changes: Renames:

Items and entities will no longer keep unknown attributes
Names of some attributes have been renamed to meet resource location requirements
generic.maxHealth 🡆 generic.max_health
zombie.spawnReinforcements 🡆 zombie.spawn_reinforcements
horse.jumpStrength 🡆 horse.jump_strength
generic.followRange 🡆 generic.follow_range
generic.knockbackResistance 🡆 generic.knockback_resistance
generic.movementSpeed 🡆 generic.movement_speed
generic.flyingSpeed 🡆 generic.flying_speed
generic.attackDamage 🡆 generic.attack_damage
generic.attackKnockback 🡆 generic.attack_knockback
generic.attackSpeed 🡆 generic.attack_speed
generic.armorToughness 🡆 generic.armor_toughness
Block placement

Ladders and tripwire hooks can now be placed on observers, redstone blocks, and target blocks
Doors, rails, buttons, pressure plates, redstone, and more can now be placed on soulsand and full-block of snow layers
Soulsand with a rail on top will no longer slow down minecarts
Block storage

BlockStates in Sections elements no longer contain values stretching over multiple 64-bit fields. If number of bits per block is not power of two (i.e. single 64-bit value can't fill whole number of blockstates) some bits will not be used. For example, if single block state takes 5 bits, highest 4 bits of every 64-bit field will be unused. That also means slight increase in storage size (in case of 5 bits, from 320 to 342 64-bit fields).

Block Tags

minecraft:climbable is now a block tag that allows datapacks to determine which blocks are, well, climbable
minecraft:soul_speed_blocks is any block that the soul speed enchantment increases speed on
Chat components

Hover event argument

style.hoverEvent parameter now has parameter contents, with contents depending on type:
For show_text - chat component
For show_item - either item id or object with fields id, count, and tag (with last one being serialized NBT)
For show_entity - object with fields: id (UUID), name (chat component), and type (entity type resource location)
Old style value argument is now deprecated (but still supported)
Commands

attribute

Adds modifies attribute on single entity. Possible syntax: Parameters:

attribute <target> <attribute> get [<scale>] - get total value of attribute
attribute <target> <attribute> base set <value> - sets base valye
attribute <target> <attribute> base get [<scale>] - get base value
attribute <target> <attribute> modifier add <uuid> <name> <value> add|multiply|multiply_base - adds modifier (fails if modifier is already present)
attribute <target> <attribute> modifier remove <uuid> - removes modifier
attribute <target> <attribute> modifier value get <uuid> [<scale>] - get value of modifier
target - single entity (note: only players, armor stands and mobs have attributes)
attribute - name of attribute (like minecraft:generic.max_health)
name - string (in optional quotes) describing human-readable name of modifier
value - floating point value (note: certain attributes have limits on final value, so your change might not be noticeable)
locatebiome

New command that locates a specified biome. Useful in creative mode when you're looking for a specific biome and don't want to fly around randomly searching for it. Syntax: locatebiome <biome> Parameters:

biome - The id of the biome to find
spawnpoint

The spawnpoint command now supports being run in any dimension.

spreadplayers

Added an optional argument to specify maximum height. New syntax: spreadplayers <center> <spreadDistance> <maxRange> [under <maxHeight>] <respectTeams> <targets>

maxHeight - Specifies the maximum height for resulting positions
UUIDs in NBT

UUIDs stored in NBT are now represented as an array of four integers. Example: {UUID:[I;1498693494,1027158888,1898994005,860320107]} Along with that a couple of fields have been renamed:

OwnerUUID of tamed animals, area effect clouds, evoker fangs and projectiles is now simply Owner
TrustedUUIDs of foxes is now Trusted
target_uuid of conduits is now Target
Custom Worlds

Added experimental support for new custom worlds
Edit world screen now has an option to export world settings to a JSON file
During world creation you can import previously exported world settings
A bunch of new parameters are exposed, but marked as experimental, meaning you can play with them, but there is no guarantee that any of them will continue working (even in the next snapshot!)
Flat level preset string lost structure settings (they are now stored in a common format for all worlds), we will restore some form of this functionality soon
Buffet world can no longer be created from server.properties, flat level settings changed a bit; better support for custom world creation on the server is coming soon
Data pack selection

Data packs can now be selected before world is created
"Re-Create" option will also copy data packs present in source world
Datapack loading

If datapack reload fails, changes will not be applied and game will continue using previous data
If existing datapacks prevent world from loading, game will give option to load world in safe mode, which loads only vanilla datapack
Changes to datapack list are stored only after successful reload
Added --safeMode option to server to load only with vanilla datapack
Game will now detect critical datapack issues, like missing required tags and prevent world from being loaded
Effects

Increased view distance in lava slightly while having the fire resistance effect
Entity Broadcasting

It is now possible to control at what range the server sends data about entities to clients.

Added an entity-broadcast-range-percentage server property controlling how close entities need to be before being sent to clients. Higher values means entities are visible further away from players but cause more network traffic. Specifies percentage of default value, so for example 50 specifies half of the default range
Fonts

Force Unicode option now switches between normal and alternative font (called uniform.json) – no reload needed
IO operations

Synchronous writes

Region files are now opened in synchronous mode to prevent data loss and corruption after crash. For performance reasons this feature is disabled by default on non-Windows clients. Status of this feature can be manually controlled by following options:

For dedicated servers: sync-chunk-writes within server.properties
For clients: syncChunkWrites within options.txt
World save format

Saving level.dat now uses randomly-named temporary files (instead of using level.dat_new every time)
player/*.dat are now saved in a way similar to level.dat (including leaving .dat_old files)
Item frames

New tags

Invisible - makes item frame invisible (item inside frame remains visible)
Fixed - prevents item frame from being broken and item inside from being removed
Jigsaw block

Jigsaw now can have one of 12 orientations
Added new property Joint type to describe if attached piece can be rotated (rollable) or not (aligned)
NBT field target_pool has been renamed to pool
attachement_type has been split into name (on parent block) and target (on child block)
Added a button in the GUI that generates a jigsaw structure starting from the jigsaw block, using given generation depth
JMX Monitoring

It is now possible to monitor the server tick times though JMX. The rationale for this is that JMX is a well known and supported monitoring technology with existing integrations and tools. This enables server admins to hook alerts and graphing tools using ordinary JMX clients and dashboards.

Enabling JMX Monitoring

A new flag enable-jmx-monitoring has been added to the server.properties file which if set to true will expose an MBean with the Object name net.minecraft.server:type=Server and two attributes averageTickTime and tickTimes exposing the tick times in milliseconds
In order for enabling JMX on the Java runtime you also need to add a couple of JVM flags to the startup as documented here
Loot Tables

Entity Predicate

Added fishing_hook sub-predicate
fishing_hook

Check properties of the fishing hook

Parameters

in_open_water - Matches whether the fishing location is open water fishing or not. A fishing location is considered to be open water if the fishing hook is in water, there are no blocks besides lily pads above water and all water blocks are source blocks with no solid underwater blocks around
Pack selection screen

Packs can now be dropped directly on data and resource pack selection screens
Dropped files and directories will be copied to appropriate places
Particles

New particle types: ash, crimson_spore, soul_fire_flame, and warped_spore
New particle types: dripping_obsidian_tear, falling_obsidian_tear, and landing_obsidian_tear
New particle type: soul
Rendering

Nailed Entity shadows to the ground
Added an Entity Distance scale option ranging from 50% to 500%
Added shader support for accessing depth buffer
Added new "Fabulous!" graphics option
This uses per-pixel blending layers for some transparent elements
Smithing recipes

There's now a smithing recipe type. Recipes of this type are used in the smithing table to upgrade one item type into another type, maintaining tags.

base - Ingredient specifying an item to be upgraded
addition - Ingredient specifying valid items to trigger the upgrade
result - Item specifying the resulting type of the upgraded item
Text style

Colors

color property can now contain RGB value prefixed by #. For example #55ff55 will result in the same color as green

Custom fonts

Chat component style now supports font property, which is resource location for font in resource pack. No entry is equivalent to minecraft:default

Fixed Bugs

Nearly 500 bugs fixed in this release.