Minecraft: Java Edition Snapshot 21w10a adds Lush Caves biome from 'Caves and Cliffs Update'

Minecraft Caves and Cliffs Update Image
Minecraft Caves and Cliffs Update Image (Image credit: Mojang Studios)

What you need to know

  • Minecraft: Java Edition is testing the next major update for Minecraft through mini-updates called snapshots.
  • The latest snapshot is 21w10a, and introduces the Lush Caves biome from the 'Caves and Cliffs Update.'
  • Lush Caves, only present in single-biome worlds, are filled with new plant-life and features.
  • This snapshot also features further tweaks to textures and the way ore is distributed in the world.

Another day, another snapshot for Minecraft: Java Edition. Mojang Studios is currently rolling out Snapshot 21w10a to interested Minecraft: Java Edition players, and it includes another host of changes hailing from the upcoming Caves and Cliffs Update.

The latest snapshot for Minecraft introduces the new Lush Caves biome, another cave variant that features a ton of all-new foliage like Azalea, Dripleaf, and Glow Berries. Right now, Lush Caves only appear in single-biome worlds and not in regular worlds, but players who don't mind doing the digging in Minecraft: Java Edition snapshots can experience all this new biome has to offer. Other notable changes include further tweaks to how ores appear in Minecraft and how they're distributed in the world.

In case you missed it, Mojang Studios officially released the 1.16.210 update for Minecraft: Bedrock Edition yesterday, which includes lots of bug fixes and general improvements.

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The full changelog for Minecraft: Java Edition Snapshot 21w10a includes:

New features

  • Added Lush Caves underground biome!
  • Added Cracked Deepslate Bricks and Cracked Deepslate Tiles
  • There is now an Infested variant of Deepslate found in the underground
  • While they will not generate in the world by default, Deepslate versions of copper, emerald and coal ores have been added for use by creators of maps and data packs

Lush Caves biome

Minecraft Caves And Cliffs Update Lush Caves

Source: Mojang Studios (Image credit: Source: Mojang Studios)
  • The Lush Caves underground biome now exists for use in single-biome worlds. It does not yet generate in other world types
  • Moss covers the floors and ceilings
  • Spore Blossoms grow from the ceiling and drip particles
  • Contains clay pools with Dripleaf Plants grow out of them
  • Contains Azalea Bushes and Flowering Azalea Bushes
  • The Azalea Tree loves to have its roots in lush caves, so if you find an Azalea Tree (either overground or in a cave) you know there is a Lush Cave beneath you
  • Cave Vines with Glow Berries grow from the ceiling and light up the caves


Minecraft Caves And Cliffs Update Texture Change (Image credit: Mojang Studios)

Minecraft Caves and Cliffs Update Image (Image credit: Mojang Studios)

Source: Mojang Studios

  • Cobbled Deepslate can now be smelted into Deepslate
  • Deepslate can now be placed along any axis
  • Lightning rods can now be waterlogged
  • Fossils in the deepest part of the underground generate with Deepslate Diamond Ore instead of Coal Ore
  • The textures of Deepslate and some of the ores have been updated

Ore distribution

Source: Mojang Studios (Image credit: Source: Mojang Studios)
  • Overworld ore generation has been tweaked
  • More emeralds in mountains
  • More lapis
  • Less copper, gold, and Redstone
  • Smaller diamond blobs, but slightly more frequent. Less diamond ore overall though
  • Less iron, and it generates lower down
  • Reduced air exposure for coal

Technical changes

  • The game now runs using OpenGL 3.2 core profile
  • The maximum size that slimes can be summoned with is now 128
  • The give command can only give up to 100 stacks of items at a time (e.g. 6400 stone or 100 iron swords)


  • Rendering is now using OpenGL 3.2 core profile. All fixed function rendering has been replaced with shader based rendering


  • Shaders are now included for all supported render states. Any shader except for the blit shader can also be replaced in resource packs. For now replacing these shaders is not officially supported and the way it works may change in the future
  • The current rendering engine uses a system similar to the post processing shader pipeline. There are some differences between both system that cater to the slightly different requirements

Bug fixes

  • Client misses inventory updates while player is manipulating items - causes invisible items
  • Shape of glow effect is based on mob's base layer
  • Only visible slots are updated clientside when you are inside an inventory
  • Lectern running /clear turns items into ghost items
  • Setblock command run by book in lectern to clear inventory run in command block causes ghost items
  • The /give command can create so many items that the game will freeze
  • Placing a sign from the offhand closes the sign UI immediately
  • /clear does not properly affect the item on the mouse pointer after crafting it
  • /spawnpoint allows players to set their spawnpoint to out-of-bounds coordinates, which crashes the game when trying to respawn
  • Guardians attack invisible axolotls
  • Normal ink sac and glow ink sac are not grouped in the creative inventory
  • Subtitles refer to Glow Item Frame as "Item Frame"
  • Ctrl + Pick Block doesn't copy block state "lit"
  • Cannot visually critical-hit a glow squid (No sound/particles)
  • Glow squid remains dark even if there is a light source block next to it
  • Glow Squid entity data (potion effects, custom name, …) does not get saved
  • FOV decreases when underwater regardless of FOV Effects accessibility setting
  • Lava does not generate at the very bottom of noise caves
  • Fossils can generate floating in caves
  • Water caves cause land to be excessively flooded
  • Bedrock can be exposed to the air at the very bottom of the new caves
  • Phantoms continously make too much flapping sounds
  • Structure blocks do not work below y=0
  • There is currently no way to craft deepslate tiles and deepslate bricks
  • Deepslate Tile Wall comes before Deepslate Brick Wall but Deepslate Bricks come before Deepslate Tiles in creative inventory
  • Emerald ore spawns in lower frequencies than it should above y=100
  • Polished deepslate slab isn't grouped with the other deepslate slabs in creative inventory
  • Crash upon replacing soul sand or magma with the other under a tall bubble column using /setblock
  • Stone Lapis Ore generating in Deepslate
  • Lava lakes generate exposed in caves
  • Coal ore can generate below Y=0 when attached to a fossil
  • Inconsistency: Cobbled deepslate cannot be smelted back into deepslate
  • Spectator vision bug
Zachary Boddy
Staff Writer

Zachary Boddy (They / Them) is a Staff Writer for Windows Central, primarily focused on covering the latest news in tech and gaming, the best Xbox and PC games, and the most interesting Windows and Xbox hardware. They have been gaming and writing for most of their life starting with the original Xbox, and started out as a freelancer for Windows Central and its sister sites in 2019. Now a full-fledged Staff Writer, Zachary has expanded from only writing about all things Minecraft to covering practically everything on which Windows Central is an expert, especially when it comes to Microsoft. You can find Zachary on Twitter @BoddyZachary.