Minecraft Wiki
Minecraft 18w21a
Java Edition 18w21a.png

Java Edition



Release date

May 23, 2018

Snapshot for



Client (.json)

Protocol version


Data version


18w21a[1] is the thirty-eighth snapshot released for Java Edition 1.13.


NBT tag
  • Added the TreasurePosX, TreasurePosY, TreasurePosZ, GotFish, and CanFindTreasure NBT tags for dolphins.
  • New option in options.txt: mouseWheelSensitivity
    • Defaults to 1.0
    • Affects sensitivity of mouse wheel in-game


  • Dolphins will now lead the player to treasures: when they are fed raw cod, they will swim to the nearest shipwreck or underwater ruins if they can find one within their search radius.
  • Mob yaw (left-right) head movement is now smooth.
Command format
  • The ench NBT tag is now called Enchantments, and no longer has number IDs in each compound.
  • Added (and fixed) item rarity colored tooltips for certain items:
Item New Rarity
Beacon Rare
Chain Command Block Epic
Command Block Epic
Conduit Rare
Creeper Head Uncommon
Dragon Egg Epic
Dragon Head Uncommon
Dragon's Breath Uncommon
Elytra Uncommon
Enchanted Golden Apple Epic
Enchanted Books Uncommon
Enchanted Items (excluding books) Rare
End Crystal Rare
Bottle o' Enchanting Uncommon
Golden Apple Rare
Heart of the Sea Uncommon
Music Discs Rare
Nether Star Uncommon
Player Head Uncommon
Repeating Command Block Epic
Skeleton Skull Uncommon
Structure Block Epic
Totem of Undying Uncommon
Wither Skeleton Skull Uncommon
Zombie Head Uncommon
Attack Speed (tools' info) Dark Green
Attack Damage (tools' info) Dark Green


29 issues fixed
From released versions before 1.13
  • MC-52974 – Host's skin not visible to other players when in LAN world.
  • MC-72866 – Item shading inside item frames does not account for rotation.
  • MC-97196/spreadplayers shows wrong error message / large number in error message when no entities were spread.
  • MC-105139 – Entity head rotation not interpolating on Yaw axis.
  • MC-116877 – Collision checking during Block placement only uses default state
From the 1.13 development versions
  • MC-122369 – Village center is offset
  • MC-122428 – Fire spread too quick
  • MC-123199 – Lighting renders incorrectly on item frames oriented vertically.
  • MC-123454 – Dispenser using spawn egg spawns mob too high.
  • MC-123455 – Using spawn egg spawns mob too high on the water and lava.
  • MC-123598 – Fence top missing texture when below fence gate.
  • MC-123773 – Weird scrolling behavior starting in 18w01a
  • MC-124954 – Jungle temple redstone wire is not connected.
  • MC-125377 – Structures from old worlds don't regenerate if opened with 1.13 standalone client/server.
  • MC-126086 – Salmon and tropical fish hitbox on land is wrongly positioned.
  • MC-126863 – Sounds made with water in spectator mode.
  • MC-127116 – When placing a wall using /setblock without specifying a block state, it is invisible; default state has up=false.
  • MC-127305 – Crash when creating a debug world
  • MC-127333 – Carpet and panes don't show the right colors on maps.
  • MC-127474 – Waterloggable blocks retain their waterlogged state when moved with pistons or slime blocks
  • MC-127586 – Mobs do not suffocate in double slabs.
  • MC-127996 – Bone meal can be put on floating water.
  • MC-128139 – Sea grass generates water source when placed on flowing water.
  • MC-128251 – Grass and mycelium can spread to dirt blocks which are submerged under general water.
  • MC-128493 – Dolphins can wear armor.
  • MC-129058 – Dolphins become permanent (can't despawn) after playing with an item.
  • MC-129708 – Armor slot icons are backwards.
From the previous development version
  • MC-129808demo.day.6 does not include the keybinding correctly.
  • MC-129849 – Upgrade from 1.6.4 destroys world, spams errors.


Video made by slicedlime:



  1. "Minecraft Snapshot 18w21a" – Minecraft.net, May 23, 2018