Minecraft: Java Edition Snapshot 21w16a adds lava aquifers, dripstone growth, and more from 'Caves and Cliffs Update'

Minecraft Caves And Cliffs Update Lava Aquifer
Minecraft Caves And Cliffs Update Lava Aquifer (Image credit: Mojang Studios)

What you need to know

  • Mojang Studios is releasing Minecraft: Java Edition Snapshot 21w16a today for testers to try out new features.
  • This continues the ongoing development for the upcoming 'Caves and Cliffs Update,' which is now split into two parts.
  • Today's snapshot includes a handful of new features for general testers, including dripstone growth.
  • There are also new features being hidden inside the new optional data pack feature for the second half of the 'Caves and Cliffs Update.'

Minecraft: Bedrock Edition was just treated with the release of Minecraft: Bedrock Edition Beta Now, the legacy version of Minecraft is getting the same treatment with Minecraft: Java Edition Snapshot 21w16a now available for testers everywhere. The latest snapshot for Minecraft continues to test out new features from the upcoming Caves and Cliffs Update.

Today, players can experience the new dripstone blocks growing over time, can use bonemeal on azalea bushes to create azalea trees, and enjoy new tweaked textures for raw ore. There's also an evolution to the datapack system introduced in Minecraft: Java Edition Snapshot 21w15a, which lets players test features even earlier that are planned to come with the delayed second half of the Caves and Cliffs Update. This includes features like new underground lava aquifers.

If you're excited for the Caves and Cliffs Update, which now releases part one this summer and part two this winter, consider taking a look at our list of best Minecraft merch, toys, and gifts for something awesome for yourself or a loved one.

The full changelog for Minecraft: Java Edition Snapshot 21w16a includes:

New features

  • Azalea and Flowering Azalea can now be bonemealed to get an Azalea Trees
  • Added dripstone growth

Dripstone growth

  • If a stalactite is hanging from a dripstone block with a water source above, it will slowly grow both the stalactite from above and a stalagmite from below
  • Growth speed is random but very slow, a single growth step can take several minecraft days
  • A stalactite will only grow up to 7 blocks long
  • A stalactite will only cause stalagmite growth if the floor or stalagmite below is within 10 blocks
  • If the stalactite tip is inside water it won't drip, and therefore won't trigger any growth
  • If the stalagmite tip is inside water it won't receive drops, and therefore won't be grown by a dripping stalactite. Same thing if there is any fluid between the two tips
  • A stalagmite or stalactite will never grow into a fluid


Source: Mojang Studios (Image credit: Source: Mojang Studios)
  • Tweaked the texture of raw ores and raw ore blocks

Caves and Cliffs Update Preview

  • Download the newly updated datapack from the Mojang Studios website
  • Aquifers below height 0 will sometimes be lava aquifers instead of water aquifers
  • Ore veins can now spawn underground

Ore veins

  • Ore veins are large, rare, snake-like underground ore formations
  • Copper veins form above height 0 and are mixed with granite
  • Iron veins form below height 0 and are mixed with tuff

Technical changes

  • Users who previously permanently declined server resource packs will now still be shown the pack prompt if the pack is mandatory (instead of being immediately disconnected)
  • The statistic for play time has been renamed to play_time
  • There is now a statistic for "Time with World Open" (total_world_time) that also includes the time when the game was paused

Bug fixes

  • stat.playOneMinute adds a value of 1 every tick
  • Statistics screen sometimes doesn't show up to date information
  • The firework rocket use statistic doesn't count rockets used for elytra boosting
  • Recipes and advancements are not granted while most GUIs are open
  • minecraft.used:minecraft.elytra not functioning
  • Debug Stick use statistic increases when not allowed to use it
  • Food that is plantable counts towards using when right clicked on the ground
  • Using a flint and steel to ingite TNT is not tracked by the in-game stats
  • Mobs don't avoid lava cauldrons when pathfinding despite of setting themselves on fire
  • Frozen State doesn't go away after respawn when on a server
  • Baby axolotls take damage when touching a solid block from below / eye height is outside of their hitbox
  • Glow Lichen can spawn underwater whilst not in a cave.
  • Glow lichen use the same color as vines on maps
  • Using bone meal on a sapling that is on a moss block consumes bone meal, but doesn't grow into a tree
  • root_vines_head is unused in-game files
  • Several dirt blocks are not part of the #minecraft:lush_plants_replaceable tag
  • Mobs can spawn on top of azaleas
  • Moss requires air above a replaceable block to spread
  • Cobwebs in mineshafts can generate as if supported by chains
  • Anvils can become damaged when only falling one block
  • Error message for commands.give.failed.toomanyitems doesn't translate item name
  • Azalea trees can generate inside of lakes (even completely submerged in water)
  • Inconsistency: Infested Deepslate can't be placed along axis
  • Inconsistency: Infested deepslate is not rotated randomly like normal deepslate
  • Cast fishing line is disconnected from the rod
  • Two mysterious white pixels can be seen in the upper left corner of the recipe book icon
  • Applying bone meal to a waterlogged big dripleaf stem creates more waterlogged big dripleaf stems
  • Silverfish infesting deepslate cause it to rotate
  • Shader compilation slows or fails the more asterisks are in a multiline comment
  • TrueType Font glyphs render incorrectly
  • Loyalty tridents disappear when your inventory is full
  • Shader includes fail to compile correctly when missing newline at end of file
  • Copper / Coal Ore in Deepslate Patches aren't Deepslate Ores
  • Entities don't stop glowing after losing the glowing effect
  • Teleport command to player does not work as in previous versions
  • Glow Squids and Axolotls Spawn in Monuments
  • Grass block isn't apart of the #dirt block tag
  • A large amount of slime or honey blocks will crash the game
  • You cannot grow azalea trees by bonemealing Azalea plants
  • minecraft.used:minecraft.candle doesn't increase when placing a candle on a cake
  • Emerald ore does not generate as intended
  • minecraft.used:minecraft.glow_ink_sac doesn't increase when applying a glow ink sac to a sign
  • minecraft.used:minecraft.ink_sac doesn't increase when applying an ink sac to a sign
  • minecraft.used:minecraft.COLOR_dye doesn't increase when applying a dye to a sign
  • minecraft.used:minecraft.bucket doesn't increase when taking powder snow, lava, or water from a cauldron using a bucket
  • minecraft.used:minecraft.glass_bottle doesn't increase when taking water from a cauldron using a glass bottle
  • minecraft.used:minecraft.glass_bottle doesn't increase when collecting honey from a beehive or bee nest
  • minecraft.used:minecraft.shears doesn't increase when carving a pumpkin
  • minecraft.used:minecraft.shears doesn't increase when collecting honeycombs from a beehive or bee nest
  • minecraft.used:minecraft.powder_snow_bucket doesn't increase when filling a cauldron with a powder snow bucket
  • minecraft.used:minecraft.lava_bucket doesn't increase when filling a cauldron with a lava bucket
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.