1.21 is an upcoming major update to Java Edition scheduled to release sometime in mid-2024. Originally announced at Minecraft Live 2023 on October 15, 2023, the update is said to focus on “combat, adventures, and tinkering”. It includes several copper block variants and trial chambers. It also includes the new crafter, new tuff block variants, and more enemies that spawn in the trial chambers.

Additions

Blocks

 Crafter

• A new block that enables the crafting of items and blocks via redstone.

• The crafter ejects one crafted item at a time when powered by a new redstone pulse, a redstone signal that is not a continuous signal.
• Upon receiving this new signal, crafters eject the recipe result from the front face.
• All the result items will be ejected together when the output result has multiple type of items.
• Crafters can be oriented in any direction when placed.
• They have a unique user interface:
  • They have a 3×3 interactable crafting grid.
  • Their crafting grid slots are toggleable, meaning that the player can change the behavior of a slot by clicking or pressing on a slot with an empty hand.
  • A “toggled” slot cannot hold any items and therefore cannot have items placed into it by other blocks such as hoppers and droppers.
  • Unlike the crafting table, the slots display a preview of the crafted item which will be crafted and ejected on the next redstone pulse but cannot be manually taken out by the player.
  • The user interface is shared between all players interacting with them, meaning that multiple players can interact with them at the same time, similar to chests and hoppers.
• They interact with other blocks in the following ways:
  • When read by a redstone comparator, the redstone signal strength is 0 to 9, where each non-empty or toggled slot adds 1 strength.
  • Hoppers can be used to both insert and pull items out of them.
  • Droppers can be used to insert items into them.
  • Moving items in from another block with a hopper or a dropper prioritizes filling items into slots following these rules:
    • Crafters prioritize the first empty slot from left-to-right and top-to-bottom.
    • If there are no empty slots then crafters prioritize the smallest stack of the same item and pick the first if there are multiple.
    • If there is a toggled slot, it is skipped. The item will then be moved into the container.
    • If the item cannot be moved, it is ejected into the world.

 Trial Spawner

• Generates in trial chambers.
• Trial Spawner is a new variant of Monster Spawners that ejects rewards upon completion and can have variable levels of challenge in multiplayer.
• The challenge level will increase for each new player a Trial Spawner notices nearby.
  • Challenge level will not decrease until it is reset during a Trial Spawner’s cooldown.
• Unlike normal spawners, a Trial Spawner will spawn a limited number of mobs proportional to its current challenge level.
  • It can only spawn a mob at positions that are within line of sight.
  • It can spawn a mob regardless of any light level requirement the mob.
  • Spawned mobs are persistent.
• Once all mobs are defeated, the Trial Spawner will eject a set of rewards proportional to the current challenge level.
  • After the rewards have been ejected, the Trial Spawner goes into cooldown for 30 minutes during which it will no longer spawn mobs.
• Trial Spawners cannot be crafted nor obtained by players in Survival – instead, they can be found naturally placed throughout trial chambers.
• Trial Spawners are extremely slow to mine and resistant to explosions, and will not drop even with Silk Touch.
• When placed in Creative, Trial Spawners have no mob type set by default.
  • The mob type can be set by interacting with it while holding a Spawn Egg.
• Creative and Spectator players cannot be detected or noticed by Trial Spawners.

 Vault

• Can be found in the trial chambers.
• Can be unlocked with a trial key.
• Each player can open the vault only once to get a reward.

Chiseled Copper

• Generates in trial chambers.
• Can be crafted from 2 cut copper slabs or can be obtained by cutting blocks of copper using a stonecutter.

• Has different levels of oxidation.
• Oxidation can be reversed with an axe.
• Honeycomb prevents oxidation from occuring.

Copper Grate

• Generates in trial chambers.
• Can be crafted from 4 blocks of copper or can be obtained by cutting blocks of copper using a stonecutter.

• Has its own exclusive breaking sound.
• Has different levels of oxidation.
• Oxidation can be reversed with an axe.
• Honeycomb prevents oxidation from occuring.
• Can be waterlogged.
• Light shines through it.
• Mobs cannot spawn on or be suffocated in it.

Copper Bulb

• Generates in trial chambers.
• Can be crafted from 3 blocks of copper, a blaze rod and a piece of redstone dust.

• Emits light based on its oxidation level. The light gets dimmer with increased oxidation.
• Has different levels of oxidation.
• Oxidation can be reversed with an axe.
• Defaults to an off state but can be toggled  with a redstone pulse.
• The block state is readable, allowing the block to function as a T flip-flop.

Copper Door

• Generates in trial chambers.
• Can be opened by a player.
• Can also be toggled opened and closed with redstone.
• Has different levels of oxidation.
• Oxidation can be reversed with an axe.
• Honeycomb prevents oxidation from occuring.

Copper Trapdoor

• Generates in trial chambers.
• Can be opened by a player.
• Can also be toggled opened and closed with redstone.
• Has different levels of oxidation.
• Oxidation can be reversed with an axe.
• Honeycomb prevents oxidation from occuring.

Tuff Stairs

• Can be crafted from tuff or can be obtained by cutting tuff using a stonecutter.

Tuff Slab

• Can be crafted from tuff or can be obtained by cutting tuff using a stonecutter.
• Can be used to craft chiseled tuff.

Tuff Wall

• Can be crafted from tuff blocks or can be obtained by cutting tuff using a stonecutter.

Chiseled Tuff

• Can be crafted from tuff slabs or can be obtained by cutting tuff using a stonecutter.

• Generates in trial chambers.

Polished Tuff

• Generates in trial chambers.
• Can be crafted from tuff or can be obtained by cutting tuff using a stonecutter.
• Can be used to craft and respective stairs , slabs  and walls .

Tuff Bricks

• Generates in trial chambers.
• Can be crafted from polished tuff or can be obtained by cutting tuff using a stonecutter.
• Can be used to craft a chiseled variant  and a respective stairs , slabs  and walls .

Items

Spawn Eggs

• Breeze spawn egg.
• Bogged spawn egg.

 Trial Key

• A reward from the trial spawners after defeating mobs.
• An item that can only be obtained from trial spawners and chests.
• Trial keys will be used to open up the vault block.

Mobs

 Breeze

• The Breeze is a hostile mob that can spawn via trial spawners in some rooms within the trial chambers.
• The Breeze moves primarily by leaping around the target, sometimes jumping quite long distances.
• An aggressive adversary, the breeze shoots volatile wind energy in the form of wind charge projectiles at its target.
• Wind charges deal a small amount of damage when colliding directly with an entity.
• After colliding with an entity or a block, wind charge projectiles produce a wind charge, which knocks back entities in the area by several blocks.
• Wind charges also have the effect of ‘activating’ certain blocks:
  • Non-iron doors and trapdoors are flipped.
  • Fence gates are flipped.
  • Buttons are pressed.
  • Levers are flipped.
  • Bells are rung and swung.
  • Lit candles (both standalone and on cake) are extinguished.
• Wind bursts do not have any effect on iron doors, iron trapdoors, or any block being held in its position by a Redstone signal.

Bogged

• A new variant of skeletons that shoot poisonous arrows.
  • They’re faster to take down with 16  × 8 health instead of 20  × 10 health.
  • They attack at a slower interval of 3.5 seconds instead of 2 seconds.
• Has a chance to drop Arrows of Poison when killed by players.
• These mossy and mushroom covered skeletons spawn naturally in swamps and mangrove swamps.
  • Can also be found spawning from trial spawners in some trial chambers.

Non-mob entities

Wind Charge

• Fired by the breeze.
• Explodes upon impact, emitting a large burst of gust particles and knocking entities back similar to a TNT explosion.
• Its explosion interacts with certain blocks, including buttons and trapdoors.
• Deals damage when colliding directly with a player or mob.
• Can be deflected, just like shulker bullets.

World generation

Trial Chambers

• Trial chambers are a new structure in the Overworld where players can explore and take on combat challenges during the mid-game.
  • Trial chambers are made out of a variety of copper and tuff blocks and can be found in different sizes from large to small.
  • Trial chambers are relatively common under deepslate layers underground.
• The layout of each trial chamber is procedurally generated, and can include traps, reward chests and a variety of combat spaces.
  • Supply chests can be found between the different rooms, and give the player blocks and items which help them navigate their trials.
  • Reward chests are guarded by challenges in each room, and can be a source of many high level enchanted books and equipment.
  • The loot found in reward chests are not final.
• Each trial chamber will include trial spawners with a melee, small melee, or ranged category:
  • Melee
    • Zombie
    • Husk
    • Slime
  • Small Melee
    • Spider
    • Cave Spider
    • Baby Zombie
    • Silverfish
  • Ranged
    • Skeleton
    • Stray
    • Skeleton with poison tipped arrows
• Each trial spawner category will only use one mob for the entire structure when generated, and these mobs are randomized for each trial chamber.
  • For example, one trial chamber might only spawn zombies, cave spiders and strays, while another might only spawn slimes, silverfish and skeletons.
  • The exceptions to this are some trial spawners in unique rooms which always spawn breezes.

General

Particles

•  Trial Spawner Detection
  • Emitted by a trial spawner upon activation.
•  Gust/Gust Emitter
  • Created in a large burst comparable to explosion particles when a wind charge explodes. The emitter spawns a number of gust particles.
• Gust Dust
  • Created in a large burst comparable to explosion particles when a wind charge explodes.
• Vault Connection
  • Created when a player stands near a vault they are yet to unlock.