Datapack Codex

Java Edition 21w43a

Minecraft Wiki article. Categories: Java_Edition_development_versions_with_vulnerabilities, Java_Edition_versions, Java_Edition_1.18_snapshots, Java_Edition_snapshots_released_in_2021, Java_Edition_snapshots, Pages_with_YouTube_videos

📌 Mirrored from Minecraft Wiki

This article is reproduced from Java Edition 21w43a on the Minecraft Wiki. Mirrored from revision 3494686. It is licensed CC BY-NC-SA 3.0 by the Minecraft Wiki contributors — not under the Codex’s CC BY-SA 4.0, and it may not be used commercially. Edits belong upstream, not here.

On this page
This page covers a development version that has a major issue under certain conditions.
 
The dedicated server for this version has a security vulnerability in the Log4j library that could be used to perform a remote code execution exploit. It can be addressed by appending a certain JVM argument to the server startup command line.[1]
Minecraft 21w43a
21w43a.jpg: Infobox image for Minecraft version 'Minecraft 21w43a'
Java Edition 21w43a.png: Infobox image for Minecraft version 'Minecraft 21w43a'
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    "title": "Minecraft 21w43a",
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        "21w43a.jpg",
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            "label": "(link to Edition article, displayed as Edition)"
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        {
            "field": "October 27, 2021",
            "label": "Release date"
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        {
            "field": "(link to Snapshot article, displayed as Snapshot)",
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            "field": "(link to Java Edition 1.18 article, displayed as 1.18)",
            "label": "Snapshot for"
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            "field": "[https://piston-data.mojang.com/v1/objects/ad67ea7db46f4ebbb1d8d5f9286401660a26ebbf/client.jar Client] ([https://piston-meta.mojang.com/v1/packages/d70716c04bc31b12276583475629e351f969cbc6/21w43a.json .json])<br />[https://piston-data.mojang.com/v1/objects/5c774a8b4e4407133eec7c4e1449c5f35974c589/server.jar Server]",
            "label": "(link to Tutorial:Installing a version#Manual version installation article, displayed as Downloads)"
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            "label": "(link to Obfuscation map article, displayed as Obfuscation maps)"
        },
        {
            "field": " <span title=\"decimal\">dec</abbr>: </span>1073741871<br /> <span title=\"hexadecimal\">hex</abbr>: </span>4000002F",
            "label": "(link to Protocol version article, displayed as Protocol version)"
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            "field": "2844",
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        },
        {
            "field": "<span class=\"plainlinks\">[https://en.wikipedia.org/wiki/Java_version_history#Java_SE_16 Java SE 16]</span>",
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21w43a is the seventh snapshot for Java Edition 1.18, released on October 27, 2021,[2] which adds the old world upgrading and fixes bugs.

Additions

Biome blending in action.

World generation

Upgrading of old worlds

  • Terrain from new chunks now blends with existing terrain from old chunks, preventing glitched borders from occurring.
  • The old bedrock layer between Y=0 and Y=4 in old chunks gets replaced with deepslate.
  • If there is bedrock at Y=0, lower places in old chunks are filled with deepslate.
    • Caves do not generate below Y=0 in old chunks but lava lakes and geodes may generate.
  • A new bedrock layer is placed at Y=-64.
  • Worlds upgraded in this snapshot have these changes permanently applied.

General

Tags

Changes

Blocks

Big Dripleaf

World generation

Aquifers

  • Water levels change less often (slightly fewer underground waterfalls).
  • Lava aquifers are slightly less common.

Caves

  • Reduced the amount of flooded caves near river and ocean coastlines.

Ocean

Seeds

  • Have been reshuffled again. Worlds don't look like as they did in previous snapshots.[3]

General

Chunk format

  • Removed chunk’s Level and moved everything it contained up.
    • Level.Entities has moved to entities.
    • Level.TileEntities has moved to block_entities.
    • Level.TileTicks and Level.ToBeTicked have moved to block_ticks.
    • Level.LiquidTicks and Level.LiquidsToBeTicked have moved to fluid_ticks.
    • Level.Sections has moved to sections.
    • Level.Structures has moved to structures.
    • Level.Structures.Starts has moved to structures.starts.
    • Level.Sections[].block_states has moved to sections[].block_states.
    • Level.Sections[].biomes has moved to sections[].biomes.
  • Added yPos the minimum section y position in the chunk.
  • Added below_zero_retrogen containing data to support below zero generation.
  • Added blending_data containing data to support blending new world generation with existing chunks.

Options

  • The Priority Updates video setting has been renamed to Chunk Builder, added tooltips to its three options, and renamed them:
    • "nearby" renamed to "Fully Blocking".
    • "by player" renamed to "Semi Blocking".
    • "none" renamed to "Threaded".

Tick

  • Changed some internal details of block and fluid ticking to improve save times.

Fixes

11 issues fixed

From released versions before 1.18

  • MC-49010 – Cloning pressure plates or buttons whilst they're activated keeps them pressed forever.
  • MC-131930 – Deep warm ocean generates without coral and sea pickles.
  • MC-156616 – Badlands layers not generating properly.
  • MC-217379 – Pufferfish don't spawn in deep warm ocean.
  • MC-224205 – Cloned big dripleaves remain tilted forever when their tilt value is not equal to "none".
  • MC-228745 – Big dripleafs can't be supported by farmland.
  • MC-238073 – Decorators are independent of world seed.

From the 1.18 development versions

  • MC-236615 – Priority updates setting has improper capitalization.
  • MC-236624 – Deep warm oceans don't count towards the "Adventuring Time" advancement.
  • MC-236970 – Badlands strata is covered by orange terracotta at Y=160 and above.
  • MC-238939 – Stone can generate in the Nether.

Videos

Videos made by slicedlime:

References

  1. ↑ "Important Message: Security vulnerability in Java Edition" – Minecraft.net, December 10, 2021.
  2. ↑ "Minecraft Snapshot 21w43a" – Minecraft.net, October 27, 2021.
  3. ↑ "Unfortunately the seeds have been shuffled again, so worlds will not look like they did in previous snapshots. Hopefully world seeds will be stable after this though, so let the real seed hunt begin!" – @henrikkniberg on X (formerly Twitter), October 27, 2021

Sources