Minecraft Snapshot 23w45a 1.20.3 / 1.21

Gameplay Changes:

The monster cage now renders the outside textures through the inside layer. This also applies to the icon in the menu, resulting in a slightly noisier texture. However, it makes sense for the cage to be transparent. Additionally, our fantastic new copper grate block previously caused damage to entities, which was unintended. As you can see, it no longer damages entities. This behavior is consistent with blocks like glass. Another issue was that mobs could naturally spawn on copper grates in darkness. This issue has been addressed, and mobs can no longer spawn on these materials.

In other changes, copper bulbs are now rendering correctly underwater. Previously, they had a rendering issue. Copper doors and trap doors now produce copper sounds instead of the generic iron sounds. Lastly, there is a significant change to copper bulbs. They will no longer allow light to pass through them.

Addition of Trial Spawner:

The Trial Spawner is a new variant of a monster generator that can have different difficulty levels in multiplayer.
Its difficulty level increases with each new detected player and will not decrease until it’s reset.
Unlike regular generators, a Trial Spawner will only spawn a limited number of monsters proportional to its current difficulty level.
It can only spawn a monster where it has a line of sight.
It can spawn a monster without considering the required light level for that monster.
Spawned monsters do not despawn.
Once all the monsters are defeated, the spawner will eject rewards corresponding to its current difficulty level.
After rewards are ejected, the Trial Spawner goes on cooldown for 30 minutes, during which it won’t spawn any monsters.
Trial Spawners cannot be crafted or obtained in Survival mode. They are also extremely slow to mine and resistant to explosions.
When placed in Creative mode, they are empty by default. Similar to regular spawners, the type of monster can be set by interacting with the spawner while holding a spawn egg.
Players in Creative and Spectator mode cannot be detected or noticed by Trial Spawners.

Addition of Breeze:

The Breeze is a hostile creature resembling the Blaze but representing the air element. It primarily moves by hopping around its target, sometimes covering long distances.
As an aggressive opponent, the Breeze harnesses volatile wind energy in the form of wind charges towards its target.
Wind charges inflict a low amount of damage when they directly collide with an entity.
After hitting an entity or a block, wind charges produce a gust of wind, pushing entities in the area for several blocks.
Gusts of wind also have an effect on certain blocks:
Doors and trapdoors (except iron) and portals are reversed.
Buttons are pressed.
Levers are toggled.
Bells are rung.
Candles are extinguished.

Addition of Trial Chambers:

Trial Chambers are new structures that generate in the depths of the Overworld, where players can explore and take on combat challenges.
They are relatively common in the slate layers of underground chasms.
Constructed from various copper and tuff blocks, Trial Chambers come in different sizes, ranging from large to small.
The layout of each Trial Chamber is procedurally generated and may include traps, chests, and a variety of combat spaces.
Supply chests can be found between different rooms, providing blocks and items that aid in the challenges.
Reward chests are guarded by combat challenges in each room and may contain high-level enchanted books and equipment.
The loot in the chests is still under development and subject to change.
Each Trial Chamber includes Trial Spawners with melee combat, small melee combat, or ranged combat categories:

Melee Combat:

• Zombie
• Husk
• Slime
• Small Melee Combat:
• Spider
• Cave Spider
• Baby Zombie
• Silverfish
• Ranged Combat:
• Skeleton
• Stray
• Skeleton with poison arrows

Each category of Trial Spawner will only use one type of creature for the entire structure during its generation, and these creatures are random for each Trial Chamber.
For example, one Trial Chamber may only spawn zombies, spiders, and strays, while another may only spawn slimes, silverfish, and skeletons.
The only exception to this is that some generators in unique rooms will always spawn Breezes.

Addition of Trial Key:

The Trial Key is a key-shaped item that can be obtained as a reward from Trial Spawners.
Currently, the key has no functionality.

Updates:

Data pack version is now 24.
The maximum value for the variable determining Jigsaw structure size has been increased from 7 to 20.
Resource pack version is now 21.
The uniform font has been updated to use Unifont 15.1.04 (instead of 15.0.06).
The only supported texture format is now .png.

Corrections:

The various corrections made in snapshot 23w45a are as follows:

[MC-131646] - Drowned generators only work in biomes where drowned spawn.


[MC-177446] - The "RootVehicle" tag in playerdata entry is not updated.


[MC-186797] - Working clocks and compasses in crafting result slot.


[MC-255244] - Link/reference NBT when using /fill command.


[MC-265702] - Text components of commands accept malformed JSON.

[MC-265747] - Hitting a TNT minecart in creative mode drops the minecart.


[MC-265875] - Compasses, clocks, and lodestone compasses work properly in crafting result slot.


[MC-266054] - Side water texture on copper blocks.


[MC-266056] - Creatures suffocate in most variants of copper grids.


[MC-266063] - Copper doors and trapdoors emit generic metal sounds when placed.


[MC-266090] - Light can pass through copper blocks.


[MC-266091] - Copper blocks do not remove faces correctly.


[MC-266096]- Copper blocks do not properly remove hidden faces.


[MC-266248] - No error message when assigning/revoking an already assigned/revoked advancement.


[MC-266256] - Accessibility button on the home screen still needs its own string.


[MC-266287] - Unable to load .dat and .nbt files (server list and saved hotbar).


[MC-266289] - Unable to save raids.dat and random_sequences.dat data.