Java Edition 1.18

1.18, the second release of Caves & Cliffs, is an upcoming major update to  set to release in late 2021. It was first announced alongside the release of 1.17 snapshot 21w15a when Mojang stated that the Caves & Cliffs update would be split in two. Features from 1.18 were developed alongside 1.17, previewed in official data packs used with a corresponding 1.17 snapshot.

Blocks

 * Will generate in the mysterious new cave biome, referred to as the "deep dark".
 * Has an animated texture.
 * May be used in redstone.
 * May be used in redstone.


 * Will generate in the deep dark biome.
 * Has a different top texture than the Sculk Block and Sculk Chute.
 * May be used in redstone.
 * May be used in redstone.


 * Will generate in the deep dark biome.
 * Made of sculk and a bone-like material.
 * May be used in redstone.
 * Glows but does not emit light, similar to the glow squid or the glow item frame.
 * Glows but does not emit light, similar to the glow squid or the glow item frame.


 * Will generate in the deep dark biome.
 * Generates in a layer on top of blocks, similar to snow.
 * Can be placed in all directions, like glow lichen.
 * Some have parts that are transparent, allowing the player to see the block it is on top of.
 * May be used in redstone as seen in this video when they talk about the sculk sensor.
 * May be used in redstone as seen in this video when they talk about the sculk sensor.

Items

 * Goat Horn
 * Dropped by a goat if it rams into a block.
 * When used for a short period of time, it makes a sound identical to the horn heard during raids.


 * Warden Spawn Egg.png Warden spawn egg.
 * Warden Spawn Egg.png Warden spawn egg.

Mobs



 * Will spawn in the new deep dark cave biome.
 * The first fully blind mob (bats, despite relying almost exclusively on echolocation, still have basic eyesight).
 * When sensing movement, it moves toward the source of the movement.
 * It follows and attacks players, mobs, and other entities that make vibrations.
 * It does not attack other Wardens.
 * When attacked, it path finds toward the player.
 * Seems to follow the same rules as the sculk sensor when detecting noise.
 * When it detects a vibration, the growths on its head rattle and light up, similar to the sculk sensor.
 * If any projectile (e.g. egg, snowball, arrow) lands near the Warden, the mob inspects the location where the projectile landed, due to the projectile creating movement and noise. This feature can be used in order to cause a distraction.
 * Does not detect players that are sneaking.
 * Can detect players that are invisible.
 * When aggravated for long enough, the warden follows the player continuously, regardless of any other distractions.
 * Will burn in direct daylight.
 * Incredibly strong, doing damage, bringing players wearing full netherite armor from full health to  health points.
 * It is the only mob that spawns in the Deep Dark.
 * Does not spawn like normal hostile mobs, but instead uses completely new spawning rules.
 * A mob designed to be extremely difficult to flee from.
 * Has a way to counter the strategy of building up 3 blocks to avoid attacks.
 * At least as fast as the player's walking speed.
 * Seems to have knockback resistance.
 * The warden's chest has a glowing core that appears to brighten and dim in tandem with the ambient lighting of the deep dark cave biome.
 * The core creates a low throbbing sound as it pulses. The sound and animation seem to speed up rapidly when the warden notices a player.
 * Is about 3.5 blocks tall, making it one of the tallest mobs in the game, exceeding the iron golem and enderman in height and width (the same).
 * Is about 3.5 blocks tall, making it one of the tallest mobs in the game, exceeding the iron golem and enderman in height and width (the same).

World generation

 * Mountains
 * Height dependent generation.
 * Revamped, featuring some new small spruce trees on the slopes and ice and packed ice above the peaks.
 * Contain goats, rabbits, snow blocks, snow layers and powder snow.
 * Iron ore, emerald ore and coal ore are found in abundance.
 * Emerald ore no longer generates in blobs of only one.
 * Can generate up to Y=256.
 * New sub-biomes.


 * Caves
 * Completely overhauled.
 * Now stretch down to Y=-59.
 * The cavern now generates in 2 layers of different stone bases depending on the depth.
 * Cavern layer above Y=0 is made up of regular stone.
 * Stone transitions to deepslate from Y=0 to Y=-7.
 * Deepslate now completely replaces stone from Y=-8 to bedrock.
 * Certain types of ores and structures still generate in the deepslate layer, as well as tuff.
 * Dirt, diorite, granite and andesite do not generate in this layer.
 * Dripstone Caves and Lush Caves now generate naturally underground.
 * Contain aquifers, bodies of water with different heights, independent of sea level (Y=63).
 * Aquifers below Y=0 sometimes generate with lava instead of water.
 * Improved old caves to blend in with the new generations of caves better.
 * New carver called crack carver, which appears as a fissure on the ground, like ravines but narrower and can go very deep.
 * New noise caves, coming in 3 forms, "cheese", spaghetti" and "noodle".
 * The original caves still exist with their generation slightly tweaked to better blend in with noise caves.
 * Cheese caves have large stone towers stretching from the bottom of the cave to the top.
 * Very large, often large enough to fly with an elytra.
 * Abundant with springs, aquifers and ores.
 * Spaghetti caves are long, thin caves that have small aquifers and are more similar to original caves.
 * Noodle caves are thinner, squigglier and more claustrophobic variants of spaghetti caves.


 * Ore veins
 * Large and rare ore formations.
 * Copper ore veins mixed with granite and raw copper block generate above Y=0.
 * Iron ore veins mixed with tuff and raw iron block generate below Y=0.

Biomes

 * Deep Dark
 * New biome at the "deepest depths of the world".
 * Wardens can spawn here.
 * Contains sculk blocks and sculk sensors.
 * Contains deepslate.
 * Generates exclusively within the deepslate layer between Y=-1 and Y=-64.
 * May contain candles.
 * May contain loot chests.
 * With the exception of spawners, no other mobs can spawn here, similar to mushroom fields.


 * Come in 5 sub-biomes:
 * The lowest layer of a mountain that look like a flowery and colder plains, with an aqua grass color.
 * Contains grass, tall grass, dead bushes, dandelions, azure bluets, cornflowers, blue orchids, poppies, daisies and alliums.
 * Rabbits and donkeys spawn in this biome.
 * Common passive mobs and horses will not spawn.
 * Resembles a snowy taiga with snow blocks instead of grass blocks.
 * The second lowest layer of a mountain.
 * Covered in snow, snow blocks, powder snow and is filled with spruce trees.
 * Only rabbits spawn in this biome.
 * The second highest layer of a mountain.
 * Covered in snow, snow blocks, powder snow and ice.
 * Goats spawn only in the snowy slopes biome.
 * The highest layer of a mountain, which will only generate if the mountain is high enough.
 * Generates if the surrounding biomes are too warm for snow capped peaks.
 * Covered in snow, snow blocks and ice.
 * The highest layer of a mountain, which will only generate if the mountain is high enough.
 * Generates if the surrounding biomes are too cold for lofty peaks.
 * Covered in snow, snow blocks, ice, and packed ice.
 * Generates if the surrounding biomes are too warm for snow capped peaks.
 * Covered in snow, snow blocks and ice.
 * The highest layer of a mountain, which will only generate if the mountain is high enough.
 * Generates if the surrounding biomes are too cold for lofty peaks.
 * Covered in snow, snow blocks, ice, and packed ice.
 * Covered in snow, snow blocks, ice, and packed ice.

Gameplay

 * While in the deep dark cave biome, the ambient lighting occasionally dims temporarily, limiting the player's visibility. This serves as a warning that the warden is nearby.
 * While in the deep dark cave biome, the ambient lighting occasionally dims temporarily, limiting the player's visibility. This serves as a warning that the warden is nearby.

Mobs

 * General
 * Hostile mobs will only spawn in areas where the light level is equal 0.
 * This change only affects block-light and not sky-light.

World generation

 * Likely change to the generation of alternate stone types, to make them appear in larger but less numerous deposits.
 * Possibly seen in a screenshot tweeted by Henrik Kniberg, in which diorite appears to generate in a long and flat horizontal strip, rather than a small unevenly shaped patch.
 * Ore generation has further rebalancing to add strategy to mining.
 * This is also largely through the addition of ore veins, which influence surrounding stone.


 * Fossils
 * The fossils in the deepest part of the underground generate with Deepslate Diamond Ore instead of Coal Ore.


 * Strongholds
 * Try to generate fully encased in stone, or deepslate at low y-levels.


 * General
 * Terrain generation is now independent from biomes, with biomes adapting to whatever terrain they happen to generate throughout.
 * This allows for natural variation in the terrain of any individual biome, both in terms of shape and elevation.
 * For example, forests and deserts could form up on a hill without needing a special biome just for that purpose.
 * This additionally allows for smoother transitions between biomes.
 * Terrain is now smoother and more extreme.

Biomes

 * Dripstone Caves
 * Now generate naturally.


 * Lush Caves
 * Now generate naturally.
 * Axolotls will now spawn here


 * Deep Warm Ocean
 * Now generate naturally.

Blocks

 * Sculk Sensor
 * May naturally generate in the Deep Dark.
 * Will appear in the creative inventory.

Items

 * Bundle
 * Can be crafted with 2 string and 6 rabbit hide.
 * Will appear in the creative inventory.
 * Will be able to be crafted.

World generation



 * Other Stones
 * Diorite or calcite and what appears to be tuff spawn in layers of stone in straight lines instead of splotches.

Blocks



 * Spore Blossom
 * Can close.


 * Azalea Log
 * Between Java Edition snapshots 21w05a and 21w10a, many blocks (flowers, leaves, grass, ferns, sweet berry bushes, small dripleafs) had a block tag called "azalea_log_replaceable", possibly implying the existence of azalea logs.

Structures

 * Underground Cabin
 * Seen in the Deep Dark biome during the Minecraft Live 2020 stream.
 * Consists of a chamber with a cobblestone floor and stripped log support beams, containing 3 barrels, a blast furnace, and a large chest, with cobwebs and candles in and around it.
 * May possibly not be a generated structure, but instead a construction built for the purpose of the Warden showcase.

Trivia

 * This is the first major update for Java Edition that is split into two updates since Adventure Update in 2011.
 * This is also the first major update that starts with "experimental" snapshots, instead of regular snapshots.