Minecraft:Java Edition 21w15a

21w15a is the seventeenth Minecraft:snapshot for Minecraft:Java Edition 1.17, released on April 14, 2021,<ref>Template:Snap</ref> which adds blocks of raw metal and the ability for Minecraft:goats to ram mobs and Minecraft:armor stands, as well as some reorders of the items in the Minecraft:Creative inventory menu. It also reverts most changes to world generation made in previous snapshots, such as height limit and Minecraft: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 were moved to 1.18.<ref>Caves and Cliffs Announcement</ref><ref>Template:Mcnet</ref><ref>Template:Cite</ref>

Additions

Template:Animate Blocks of raw metal

Added Minecraft:block of raw iron, Minecraft:block of raw copper and Minecraft:block of raw gold.
- Minecraft:Piglins don't pick up blocks of raw gold,<ref>Template:Bug</ref> and don't get angry when a nearby player mines them.<ref>Template:Bug</ref>
- Obtained through Minecraft:crafting, and can be crafted back into their respective raw metal.
- Can't be Minecraft:smelted.<ref>Template:Bug – resolved as "Invalid"</ref>

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 Template:Nbt compound field that can contain any data.

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.

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

Raw metal

Now avoid walking on Minecraft:powder snow.
Can now ram other mobs and Minecraft:armor stands to knock them a few blocks.
- Minecraft:Creepers don't explode when attacked by a goat.

Gain one and a half minutes of moisture when a splash water bottle is thrown at them.

World height increase has been reverted and is now once again 256 blocks (from Y=0 to Y=255).
Worlds created in snapshot Minecraft:21w05b or any earlier version can now once again be opened.
Worlds created in any version between snapshot Minecraft:21w06a and Minecraft:21w14a can no longer be opened.
- This can be bypassed by setting the data version in level.dat to anywhere from 2692 and below, to 2709 or higher. However, this causes issues.
Creating a new world with the Prototype Data pack (or putting the data pack in an existing world with the bypass above) can try out the world generation for the later update using a data pack which activates the changes as an experimental custom world.

Minecraft:Ore distribution

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