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Minecraft 21w37a
Java Edition 21w37a.png

Java Edition



Release date

September 15, 2021

Snapshot for



Client (.json)

Obfuscation maps


Protocol version

 dec: 1073741865
 hex: 40000029

Data version


21w37a is the first proper snapshot for Java Edition 1.18, released on September 15, 2021,[1] which adds the contents of the previous experimental snapshots and brings more parity with Bedrock Edition.



  • /jfr
    • When enabled, begins profiling with Java FlightRecorder, as well as the following custom events:
      • minecraft.ServerTickTime: Sampling event exposing average server tick times in intervals of a second
      • minecraft.ChunkGeneration: Time taken to generate individual chunk stages
      • minecraft.PacketRead / minecraft.PacketSent: Network traffic
      • minecraft.WorldLoadFinishedEvent: Initial world loading duration
    • The profiling can be stopped in-game by using /jfr stop.
  • Added illageralt, the rune-like font from Minecraft Dungeons.
    • Currently only usable via commands
Loot tables
  • Added the type field, which is mandatory.
    • Written into BlockEntityTag.id to ensure that the tag can be migrated correctly between versions
  • Can now disable lightning flashes, which prevents lightning from making the sky flash. Lightning bolts themselves will still appear.
  • The device the game outputs audio to can now be chosen in-game.
  • Added "Priority updates" to video settings.
    • Determines as to which chunk sections are updated synchronously in a single frame.
      • Three options:
      • nearby, which corresponds to how chunk sections were updated before 21w37a, and by player and none, which reduce stuttering when placing or removing blocks.
        • However, the latter two options may cause rare visual delays in world updates. These options also appear to be improperly capitalized.[2]
  • Added subtitles for various bundle sounds.



Enchanting Table
  • Now emits a light level of 7.
Cave Vines, Kelp, Twisting Vines and Weeping Vines
  • Will stop growing if shears are used on the tip.


  • Now only spawn in lush caves.
  • Now have their own mob cap.
Vindicators, pillagers, and evokers


  • The Sneak and Sprint, and Auto-jump options have been moved to the Controls tab.
  • Render distance now causes chunks to load in a cylinder shape around the player instead of a square.
  • The splash "[this splash text has been delayed until part 2]" has been changed to "[this splash text is now available]".
  • Renamed the lava_pool_replaceables block tag to lava_pool_stone_cannot_replace.
  • Worlds last opened before Java Edition 1.2 can no longer be opened.
    • These worlds must be opened in a version prior to 21w37a (preferably between Java Edition 1.2 and Java Edition 1.6.4).
    • An error will be shown when attempting to open these worlds.
  • Worlds from before 21w37a currently cannot be opened, though this will change before 1.18 is released.
  • Removed length limits for scoreboards, score holders and team names.
  • Data pack format has been increased to 8.

Known issues[]


44 issues fixed
From released versions before 1.18
  • MC-29274 – Withers will not pursue players in survival mode unless attacked.
  • MC-30560 – River through eroded badlands biome generates floating rock formations at water surface.
  • MC-54545 – Client render distance doesn't adjust to server render distance if they are different, causing faulty chunk loading.
  • MC-65628 – Desert pyramids generate underground when using amplified or custom terrain.
  • MC-123277 – Too long scoreboard objectives and team names are not detected when commands are parsed.
  • MC-129266 – Jagged ocean transitions and slower biome generation.
  • MC-138801 – The interactions between a biome and another biome and its variants are inconsistent.
  • MC-140690 – Giant spruce taiga hills have no difference with giant spruce taiga.
  • MC-159025 – Drowned do not spawn in warm ocean biomes.
  • MC-160710 – Chat messages written while sleeping are deleted after waking up.
  • MC-166423 – Splash water bottles don't damage endermen.
  • MC-182362 – Score callbacks with a too long name break callback chain.
  • MC-202376 – Rabbits, instead of spawning on snow blocks, spawn on snow layers.
  • MC-208601 – Axolotls do not avoid danger when pathfinding.
  • MC-212113 – Glow lichen can spawn underwater whilst not in a cave.
  • MC-213779 – FPS dramatically decreases when looking up in world with large height.
  • MC-214783 – Oceans generate with stone floors.
  • MC-214797 – Pointed dripstone can generate floating at transitions between local water levels.
  • MC-214799 – Aquifiers sometimes create air pockets.
  • MC-214864 – Hard edges when new caves generate near surface.
  • MC-214989 – Isolated floating mineshaft platform.
  • MC-215296 – Mineshafts often don't generate in floating island worlds.
  • MC-215876 – Dirt can generate below y=0 from mineshafts.
  • MC-216784 – Ruined portals don't generate below y=0.
  • MC-216952 – Some chunks interrupting with cave systems filled with blocks.
  • MC-216967 – Kelp and seagrass can generate in aquifers.
  • MC-217465 – Unnatural shape looking like a chunk border but appears to be completely unrelated to chunk borders.
  • MC-217509 – Inefficient generation of aquifers, noise caves and ore veins.
  • MC-219774 – Magma blocks spawn everywhere underwater in 21w10a.
  • MC-219946 – Weird flat sections of terrain.
  • MC-221777 – Horses donkeys, mules, llamas, and trader llamas do not follow players holding food.
  • MC-221815 – Flat roofs in underwater caves.
  • MC-221917 – Dripstone, pointed dripstone, and cave magma generate in oceans.
  • MC-222051 – Iron ore generation was not increased in 21w13a.
  • MC-222379 – Magma can spawn under air in underwater caves.
  • MC-223044 – Floating water can generate in ravines.
  • MC-223051 – Dripstone can generate in surface lakes.
  • MC-223148 – New extended height message goes behind the scrolling bar.
  • MC-226184 – Axolotls pathfinding to water can sometimes fall in wide holes.
  • MC-227244 – Ore blocks from ore veins float in underwater magma ravines.
  • MC-230343 – Parity issue: enchanting tables do not emit a light level of 7.
  • MC-231721 – Animals named "Dinnerbone" do not look at the food correctly.
  • MC-231863 – Game crashes when trying to access the Realms settings.
  • MC-233050#lava_pool_stone_replaceables tag name is misleading.


Video made by slicedlime: