Java Edition 21w06a

Not to be confused with 20w06a.

21w06a is the ninth snapshot for Java Edition 1.17, released on February 10, 2021, which adds new cave generation and a new build height limit.

Worlds created prior to this snapshot cannot be loaded in this version, due to there being no upgrade path towards the new height.

World generation

 * Caves
 * Added aquifers and new noise caves, which come in two "flavors," 'spaghetti' and 'cheese' caves.


 * Spaghetti caves
 * Long noodle-like caves, sometimes wide like tagliatelle.


 * Cheese caves
 * Like the holes in swiss cheese, ofter form caverns of various sizes.


 * The old cave generation still generates, combining with the new caves.


 * The new generation also form cave entrances when they intersect with land.


 * Aquifers
 * Used to generate bodies of water in new caves. As of now, it's only used below Y=31, meaning any noise caves between the two heights are flooded with water. This will be fixed later.


 * Magma blocks may generate at the bottom of these new water bodies, creating downward bubble columns.


 * Replaces the old underwater cave carvers/canyons.


 * Mineshaft
 * Mineshaft pieces no longer generate if they were fully floating in the air.


 * Corridors now generate with log pillars for support if needed.


 * There are no more floating cobwebs.

Blocks

 * Hanging Roots
 * The texture has been changed.


 * Small Dripleaf
 * The texture has been changed.

General

 * World
 * Raised the height limit to 384 blocks.
 * The height limit now goes from -64 up to 320 blocks.