Minecraft Wiki
Minecraft 21w16a
Java Edition 21w16a.png

Java Edition



Release date

April 21, 2021

Snapshot for



Client (.json)
Data pack[note 1]

Obfuscation maps


Protocol version

 dec: 1073741847
 hex: 40000017

Data version


21w16a is the eighteenth snapshot for Java Edition 1.17, released on April 21, 2021,[1] which adds dripstone growth and the ability to grow azalea trees.



Pointed 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 in-game 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 will not trigger any growth.
  • If the stalagmite tip is inside water or there is a fluid between the two dripstone blocks, it will not receive the water drops, and therefore will not be grown by a dripping stalactite.
    • A stalagmite or stalactite will never grow into a fluid.


  • Added Russian (Pre-revolutionary) language.
  • Added Chinese Traditional (Hong Kong) language.


Changes have been made to the official Caves & Cliffs world generation preview datapack, which gives early access to the world generation coming in Java Edition 1.18.

Ore veins
  • Large rare snaking collections of ore found underground.
    • Copper mixed with granite is found at and above Y=0; iron mixed with tuff is found below Y=0.



Azalea and flowering azalea
  • Can now be fertilized with bone meal to form Azalea Trees.
Block of raw iron and block of raw gold
  • Tweaked the textures of these blocks.
Emerald ore
Infested deepslate
  • Can now have random texture rotation like deepslate.
Small dripleaf
Grass block, mycelium, moss block
  • Grass, tall grass, ferns, tall ferns, sweet berry bushes, saplings, flowers, azaleas, sugar cane, dead bushes, and bamboo can now be placed on these blocks.
  • Pumpkins and melons can now grow onto these blocks.
  • Endermen can now pick up these blocks.


Raw metal
  • Tweaked the texture of raw ores.


Recipe book
  • The recipes for stonecutting diorite into polished diorite slabs and stairs now unlocks when the player has diorite as opposed to polished diorite.


  • Renamed the statistic for play time to play_time.
  • Included time when game paused for "Time with World Open" (total_world_time).
Resource pack prompt
  • 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.
  • Added grass blocks, mycelium, and moss blocks to the dirt block tag.
  • Tweaked some tags to no longer unnecessarily mention blocks if they're in the dirt block tag.
  • Tweaked the lush_ground_replaceable block tag to call the moss_replaceable tag instead of the lush_plants_replaceable tag, as well as adding gravel and sand.
  • Removed the lush_plants_replaceable block tag.
  • Removed the unused rooted_vines_head.png texture.
  • Removed stray pixels from the recipe book GUI button.


Changes have been made to the official Caves & Cliffs world generation preview datapack, which gives early access to the world generation coming in Java Edition 1.18.

  • Aquifers below Y=0 will sometimes be made of lava.


56 issues fixed
From released versions before 1.17
  • MC-29522stat.playOneMinute adds a value of 1 every tick.
  • MC-55775 – Statistics screen sometimes doesn't show up to date information.
  • MC-111534 – The firework rocket use statistic doesn't count rockets used for elytra boosting.
  • MC-117653 – Recipes and advancements are not granted while most GUIs are open.
  • MC-136560minecraft.used:minecraft.elytra not functioning.
  • MC-136681 – Debug Stick use statistic increases when not allowed to use it.
  • MC-157116 – Food that are plantable counts towards using when right click on the ground.
  • MC-180529 – TrueType fonts crash on Intel Graphics.
  • MC-190128 – Using a flint and steel to ingite TNT is not tracked by the in-game stats.
  • MC-223558minecraft.used:minecraft.glass_bottle doesn't increase when taking water from a cauldron using a glass bottle.
  • MC-223563minecraft.used:minecraft.glass_bottle doesn't increase when collecting honey from a beehive or bee nest.
  • MC-223638minecraft.used:minecraft.shears doesn't increase when carving a pumpkin.
  • MC-223639minecraft.used:minecraft.shears doesn't increase when collecting honeycombs from a beehive or bee nest.
  • MC-223755minecraft.used:minecraft.water_bucket doesn't increase when filling a cauldron with a water bucket.
From the 1.17 development versions
  • MC-203637 – Mobs don't avoid lava cauldrons when pathfinding despite of setting themselves on fire.
  • MC-205236 – Frozen State doesn't go away after respawn when on a server.
  • MC-208598 – Baby axolotls take damage when touching a solid block from below / eye height is outside of their hitbox.
  • MC-212863 – Glow lichen use the same color as vines on maps.
  • MC-213804 – Azalea and flowering azalea undersides are darkened.
  • MC-213845 – Big dripleaf plants cannot be placed on top of each other.
  • MC-213893 – scoreboard minecraft.used:minecraft.glow_berries triggers when right clicking the ground.
  • MC-213927 – Using bone meal on a sapling that is on a moss block consumes bone meal, but doesn't grow into a tree.
  • MC-213998root_vines_head is unused in-game files.
  • MC-214129 – Several dirt blocks are not part of the #minecraft:lush_plants_replaceable tag.
  • MC-214293 – Mobs can spawn on top of azaleas.
  • MC-215043 – The new small dripleaf's stem texture isn't connected properly with the upper leaf.
  • MC-216787 – Cobwebs in mineshafts can generate as if supported by chains.
  • MC-217411 – Anvils can become damaged when only falling one block.
  • MC-218590 – Error message for commands.give.failed.toomanyitems doesn't translate item name.
  • MC-218614 – Inconsistency: Infested Deepslate can't be placed along axis.
  • MC-218637 – Inconsistency: Infested deepslate is not rotated randomly like normal deepslate.
  • MC-219211 – Two mysterious white pixels can be seen in the upper left corner of the recipe book icon.
  • MC-219851 – Applying bone meal to a waterlogged big dripleaf stem creates more waterlogged big dripleaf stems.
  • MC-219903 – Silverfish infesting deepslate cause it to rotate.
  • MC-220024 – Shader compilation slows or fails the more asterisks are in a multiline comment.
  • MC-220187 – Hitbox of azalea and flowering azalea is incorrect.
  • MC-220190 – When bone mealing moss blocks with no spreadable blocks nearby, they don't grow grass, bushes and moss carpets.
  • MC-220307 – TrueType Font glyphs render incorrectly.
  • MC-220641 – Loyalty tridents disappear when your inventory is full.
  • MC-220887 – Shader includes fail to compile correctly when missing newline at end of file.
  • MC-221258 – Cannot place sugar cane, bamboo and dead bushes on moss blocks.
  • MC-221628 – Entities don’t stop glowing after losing the glowing effect.
  • MC-221652/teleport command to player does not work as in previous versions.
  • MC-221655 – Glow Squids and Axolotls Spawn in Monuments.
  • MC-222004 – Grass block isn't in the #dirt block tag.
  • MC-222517 – A large amount of slime or honey blocks will crash the game.
  • MC-222684 – You cannot grow azalea trees by bonemealing Azalea plants.
  • MC-222778minecraft.used:minecraft.candle doesn't increase when placing a candle on to a cake.
From the previous development version
  • MC-223260 – Emerald ore does not generate as intended.
  • MC-223382 – A marker's data tag can be shared among multiple markers.
  • MC-223553minecraft.used:minecraft.glow_ink_sac doesn't increase when applying a glow ink sac to a sign.
  • MC-223554minecraft.used:minecraft.ink_sac doesn't increase when applying an ink sac to a sign.
  • MC-223555minecraft.used:minecraft.COLOR_dye doesn't increase when applying a dye to a sign.
  • MC-223557minecraft.used:minecraft.bucket doesn't increase when taking powder snow, lava, or water from a cauldron using a bucket.
  • MC-223756minecraft.used:minecraft.powder_snow_bucket doesn't increase when filling a cauldron with a powder snow bucket.
  • MC-223757minecraft.used:minecraft.lava_bucket doesn't increase when filling a cauldron with a lava bucket.


Videos made by slicedlime:


  1. "Minecraft Snapshot 21w16a" – Minecraft.net, April 21, 2021


  1. Re-enables features set to release for 1.18.