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 holiday release, as seen in the Caves and Cliffs Announcement with Agnes Larsson and Henrik Kniberg.

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.

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 has been switched back to the 1.16 levels.
 * 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.


 * 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 returned to the 1.16 setup.
 * Copper now generates between the bottom of the world and height 192, being most common around height 96.

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.

Trivia

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