Minecraft Wiki
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 snapshot for Java Edition 1.18, released on September 15, 2021,[1] which adds the contents of the previous seven experimental snapshots and brings more parity with Bedrock Edition.

Any worlds from previous versions can not be opened in this version.



  • /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
  • Now stop growing if shears are used on the tip.
    • This action changes the age block state of the tip to 25.
Snow Block
  • Reverted change allowing plants to be placed on snow blocks.
    • This reversion results in the lack of vegetation in the grove biome.


  • Have been removed from the creative inventory once again.
  • Can once again no longer be crafted.
  • Only accessible through commands once again.
  • Durability has been increased to 465.


  • Now have their own mob cap.
Vindicators, pillagers and evokers
Feedable mobs
  • All feedable mobs (except sheep) named Dinnerbone will now look at the player correctly.

World generation[]

Stone shores
Stony peaks


Data packs
  • Data pack version number has been increased to 8.
  • 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.
  • Removed length limits for scoreboards, score holders and team names.
  • 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_stone_replaceables block tag to lava_pool_stone_cannot_replace.


68 issues fixed
From released versions before 1.18
  • MC-7200 – Cave/tunnel generation may cut tunnels a bit too soon.
  • 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-72831 – Water lakes can generate in deserts.
  • MC-85975 – Slimes don't spawn in the swamp hills biome.
  • MC-101917 – Andesite, diorite and granite won't generate above a height of about 80.
  • MC-123277 – Too long scoreboard objectives and team names are not detected when commands are parsed.
  • MC-125033 – Old cave and ravine generation gets cut off unnaturally on chunk borders near water.
  • MC-126133 – Undercover ravines sometimes generate cut off at chunk borders.
  • MC-129266 – Jagged ocean transitions and slower biome generation.
  • MC-132175 – Beaches generate along swamp hills when bordering an ocean.
  • MC-132429 – Sand beaches generate when bordering gravelly mountains biomes.
  • MC-134407 – Ocean ravines spawning underground with a stone roof on top.
  • MC-138801 – The interactions between a biome and another biome and its variants are inconsistent.
  • MC-140151 – Modified jungle edge biomes only generate when a jungle borders a swamp hills biome.
  • 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-166238 – Trees can generate on mycelium.
  • MC-166423 – Splash water bottles don't damage endermen.
  • MC-167277 – Swamp hills don't naturally generate seagrass.
  • MC-175929 – Ice spikes get cut off below height limit on AMPLIFIED worlds.
  • MC-182362 – Score callbacks with a too long name break callback chain.
  • MC-186042 – Plains biome is always generated when a swamp borders a desert, snowy tundra or snowy taiga.
  • MC-188096 – Gravelly mountains+ is no different than gravelly mountains.
  • MC-190363 – Some biomes generate as "Single biome" worlds in "Floating islands" world type.
  • MC-199298 – Strongholds don't generate in bamboo jungles.
  • MC-200230 – Anomalous stripes/grid ice generation in frozen ocean biome.
  • MC-202376 – Rabbits, instead of spawning on snow blocks, spawn on snow layers.
  • MC-208352 – Dark forest hills don't generate small patches of plains or sunflower plains, but dark forest does.
  • MC-208353 – Several hills biomes do not generate sporadically replacing patches of their regular biome counterparts.
  • MC-208601 – Axolotls do not avoid danger when pathfinding.
  • MC-212113 – Glow lichen can spawn underwater whilst not in a cave.
  • MC-213779 – FPS drops when looking up in a tall world (4064 blocks).
  • MC-214335 – Flower forest is much steeper than regular forest.
  • MC-214783 – Oceans generate with stone floors.
  • MC-214797 – Pointed dripstone can generate floating at transitions between local water levels.
  • MC-214799 – Aquifers sometimes create air pockets.
  • MC-214864 – Hard edges when new caves generate near surface.
  • MC-215062 – Weird aquifer barrier generator and water in incorrect states.
  • MC-215296 – Mineshafts often don't generate in floating island worlds.
  • MC-215876 – Dirt can generate below Y=0 from mineshafts.
  • MC-216362 – Jukeboxes that have been placed don't stack with jukeboxes that have not been placed.
  • MC-216448 – River generates over a ravine.
  • 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-217136 – Random noise pillars generating mid air.
  • 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-221679 – End fog loses its gradient when under Y=0.
  • 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 – Extended height message goes behind the scrolling bar.
  • MC-225781 – The noise cave lava level and the cave carver lava level generate 1 block apart.
  • 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-231863 – Game crashes when trying to access the Realms settings.
  • MC-233050#lava_pool_stone_replaceables tag name is misleading.


Videos made by slicedlime:


  1. "Minecraft Snapshot 21w37a" – Minecraft.net, September 15, 2021
  2. MC-236615