Java Edition 21w15a

21w15a is the seventeenth snapshot for Java Edition 1.17, released on April 14, 2021, which adds the ability for goats to ram mobs and armor stands, as well as blocks of raw metal. It also reverts most changes to world generation made in previous snapshots, such as height limit and cave types. Due to the technical challenges on the new cave generations and the effects of the COVID-19 pandemic on the developers, these changes will be moved to a future version.

Blocks

 * Block of Raw Metal
 * Added block of raw iron, block of raw copper and block of raw gold.
 * Piglins don't pick up blocks of raw gold, and don't get angry when a nearby player mines them.
 * Can be obtained through crafting.
 * Can be crafted into their respective raw metal.
 * Can't be smelted.

Non-mob entities

 * Marker
 * Added the Marker entity meant for custom use cases like map making and data packs.
 * Only exists on the server side, is never sent to clients.
 * Does not do any updates of their own.
 * Has a compound field that can contain any data.

Command format

 * New debug subcommand executes command with same syntax as function.
 * Every executed command, message (even if it would be normally invisible), result or error is stored to file.
 * Cannot be run from inside functions.

Sounds

 * Bone Meal
 * Added sounds for using bone meal.

General

 * server.properties arguments
 * Adds a custom message to be shown on resource pack prompt when  is used.
 * Expects chat component syntax, can contain multiple lines.
 * Expects chat component syntax, can contain multiple lines.

Blocks

 * Gold Ore, Lapis Lazuli Ore, Deepslate Copper Ore, Deepslate Lapis Lazuli Ore
 * Slightly tweaked the textures of these blocks.

Items

 * Raw Metal
 * Tweaked the textures of raw ore items.

Mobs

 * Goats
 * Goats now avoid walking on powder snow.
 * Goats can now ram other mobs and armor stands to knock them a few blocks.
 * Creepers no longer explode when attacked by a goat.

World generation

 * World height
 * World height increase has been reverted and is now once again 256 blocks (from Y=0 to Y=255).
 * Worlds created in snapshot 21w05b or any earlier version can now once again be opened.
 * Worlds created in any version between snapshot 21w06a and 21w14a can no longer be opened.
 * This can be bypassed by setting the data version in  to anywhere from 2692 and below, to 2709 or higher, then putting the Prototype Datapack into the world's   folder. However, this may cause issues.


 * Caves
 * Noise caves and aquifers have been switched off.
 * Cave and ravine carvers have been returned to their old settings.
 * Crack carvers have been switched off.


 * Ore distribution
 * Ore distribution has been reverted to the pre-1.17 distribution.
 * Copper ore now generates between the bottom of the world and Y=192, being most common around Y=96.


 * Tuff
 * Now generates in blobs from Y=0 to Y=16.

General

 * Title screen
 * The main menu background is now in an amethyst geode.


 * Creative inventory
 * Reordered some blocks in the Building Blocks tab in the creative menu.
 * Deepslate emerald ore was moved among other ores.
 * Cracked deepslate bricks and Cracked deepslate tiles was moved at other deepslate blocks.
 * Block of copper was moved among other "metal" blocks.
 * Dripstone block was moved among other "stone" blocks.

Trivia

 * This is the first time the world height was decreased since Infdev.