Time for an Advanced snapshot! In this snapshot, you can also open worlds from previous versions again - with one big warning! The blending technology we intend to introduce for Caves & Cliffs: Part II is not yet available. If you open an old world in this snapshot it will be upgraded with air under the current bottom of the world and visible chunk borders to new areas.

We highly recommend backing up your world before loading it in this snapshot.

New Features in 21w39a

Added Caves & Cliffs: Part II Advancements

Advancements

Added "Caves & Cliffs" for falling from top to bottom of the Overworld
Added "Feels like home" for riding strider on lava for 50 blocks in the Overworld
Added "Star Trader" for trading with a villager at the build height limit
Added "Sound of Music" for playing music with a jukebox in a Meadow biome

Changes in 21w39a

Tweaked peaks to make small mountains look more like proper jagged mountain peaks instead of flat hilly mounds
The lone trees in Meadows now always contain a bee nest
Drowned can spawn in aquifers inside dripstone caves
Zombies don't spawn in dripstone caves
Buried treasure chests can now contain water breathing potions
Changed default brightness to 50
Redesigned how effects look in the inventory screen, to allow them to show even with recipe book open

Effects

Your list of effects are now shown to the right of your inventory, instead of the left side
When the inventory effects list is visible, it will be hidden from the game view to reduce screen clutter
There's now two modes of seeing the effect list: compact and classic
- Classic is the pre-existing list of effects, one after another
- Compact is a single icon for each effect, suitable for small screen estate
The game will automatically switch between the two looks to suit the available screen estate (including having the recipe book open)

Technical Changes in 21w39a

Added fall_from_height and ride_entity_distance advancement triggers
Changed nether_travel to match other similar triggers
Added new loot table function set_potion
Changes to the on-disk chunk format
Resource pack format has been increased to 8
Standalone server.jar now bundles contains individual libraries instead of being flat archive

Advancements

New triggers

`fall_from_height`

Triggered when a player lands after falling
Conditions:
- player - a player for which this trigger runs
- start_position - location predicate for last position before falling started
- distance - predicate for distance between start_position and player

`ride_entity_in_lava`

Triggered for every tick when player rides in lava
Conditions
- player - a player for which this trigger runs
- start_position - position where riding started (first tick on lava)
- distance - predicate for distance between start_position and player

Changed triggers

`nether_travel`

entered condition renamed to start_position
exited has been removed, since it was identical to player.location

Loot Tables

New functions

`set_potion`

Sets Potion tag on any item

Parameters:

id - potion id

World Data: Chunk Format

Chunk's Level.Sections[].BlockStates & Level.Sections[].Palette have moved to a container structure in Level.Sections[].block_states
Chunk's Level.Biomes are now paletted and live in a similar container structure in Level.Sections[].biomes
Chunk's Level.CarvingMasks[] is now long[] instead of byte[]

Resource Pack format

minecraft/textures/gui/container/inventory.png now contains an extra sprite for a thin-layout version of the effect list in the inventory

Server bundling

server.jar now bundles individual libraries instead of merging all the files into single archive
This change is meant to solve certain problems related to Java modules
On startup, server.jar will unpack libraries into directory configured by bundlerRepoDir (default: working directory)
To run different main class than server, use bundlerMainClass property (for example java -DbundlerMainClass=net.minecraft.data.Main -jar server.jar --reports) or unpack jar manually and use contents of META-INF/classpath-joined for command line

Fixed bugs in 21w39a

MC-116359 Status effects aren't displayed in inventory when recipe book is open
MC-149822 Bottom border on status effect displays in the inventory is missing
MC-193348 Status effect bars shift the player's inventory in creative mode
MC-196723 Potion effects obtained in creative mode while in inventory do not show up until reopening inventory
MC-214894 Bamboo generates in caves under jungles
MC-214959 Sugar cane generated in cave
MC-218167 Chatting causes lag to occur
MC-236755 "Feature Placement" Crash / java.lang.IndexOutOfBoundsException: Index 0 out of bounds for length 0
MC-236903 Naturally generated cave vines have an age between 17-25
MC-237505 Certain Biome Builder debug values do not change

Minecraft Snapshot 21w39a