Java Edition 18w21a

18w21a is the thirty-eighth snapshot for Java Edition 1.13 released on May 23, 2018^[1].

NBT format

• Added the TreasurePosX, TreasurePosY, TreasurePosZ, GotFish, and CanFindTreasure tags for dolphins.

Settings

• New option in options.txt: mouseWheelSensitivity
  • Defaults to 1.0
  • Affects sensitivity of the  Scroll Wheel in-game

Mobs

• Dolphins now lead the player to treasures: when they are fed raw cod, they 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.

NBT format

• The ench tag is now called Enchantments, and no longer has number IDs in each compound.

General

• 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-129808 – demo.day.6 does not include the keybinding correctly.
• MC-129849 – Upgrade from 1.6.4 destroys world, spams errors.

• This snapshot was released on World Turtle Day.