Java Edition 21w40a

21w40a is the fourth snapshot for Java Edition 1.18, released on October 7, 2021, merged and renamed some Biomes, tweaked world generation and mob spawning.

Biomes

 * Merged similar biomes and renamed some biomes.
 * Non-cave biomes (e.g. Savannas) no longer change with height.
 * Tweaked the relative size of some biomes, to match 1.17 a bit closer.
 * Increased the average size of most biomes.

Blocks

 * Copper Ore
 * Now drop 2-5 Raw Copper when mining instead of 2-3.


 * Stonecutter
 * Block of Copper can be converted to 4 Cut Copper using stonecutter.

Mobs

 * Axolotls
 * Now only spawn in water which above Clay Blocks in Lush Caves.


 * Cod, Salmon, Pufferfish, Tropical Fish, Squid, and Dolphins
 * Now only spawn in water from Y=50 to Y=64.
 * Additionally, tropical fishes now also spawn in lush caves at any height.


 * Glow Squids
 * Now only spawn in water blocks under Y=30.


 * Goats
 * No longer spawn in Stony Peaks.


 * Zombies
 * Now also spawn in Dripstone Caves again.

World Generation

 * Dungeons
 * Increased the amount of dungeons, especially below Y=0.


 * Gravel
 * Now generates below Y=0.


 * Lakes
 * Removed, because Aquifers could provide local water levels.


 * Magma Blocks
 * Slightly increased the frequency of underwater magma.


 * Ore distribution
 * Added more unexposed Diamonds.
 * Iron ore now generates above Y=80, generate more when go higher.
 * Gold now generated below Y=-48 in Badlands biome and its variants.


 * Villages
 * Now slightly more spread out.


 * General
 * Bedrock layers generate dependent on the world seed now.

General

 * AI
 * Optimized AI for Axolotls, Goats, Hoglins, Zoglins, Piglins, Piglin Brutes and Villagers.