Pre-release protocol

This page documents the changes from the last stable Minecraft release (currently 1.19.4, protocol 762) to the current pre-release (currently 1.20-pre4, protocol Snapshot 137). Note that this page contains bleeding-edge information that may not be completely or correctly documented.

One who wishes to commandeer the merging of this into Protocol when an update is made must be sure to respect any changes that may have occurred to the respective packets there.

Contents

Data types

No changes so far.

Packets

ID	Packet name	Documentation
Play clientbound
0x24	Chunk Data and Update Light	Current	Pre
0x27	Update Light	Current	Pre
0x28	Login (play)	Current	Pre
0x31	Open Sign Editor	Current	Pre
0x36	End Combat	Current	Pre
0x38	Combat Death	Current	Pre
0x41	Respawn	Current	Pre
0x43	Update Section Blocks	Current	Pre
0x69	Update Advancements	Current	Pre
0x6B	Feature Flags	Current	Pre
0x6D	Update Recipes	Current	Pre
Play serverbound
0x2E	Update Sign	Current	Pre

New/modified data types

No changes so far.

Entity Metadata

No changes so far.

Entity

No changes so far.

Block Actions

No changes so far.

Inventories

Type	Name	Description
0	minecraft:generic_9x1	A 1-row inventory, not used by the notchian server.
1	minecraft:generic_9x2	A 2-row inventory, not used by the notchian server.
2	minecraft:generic_9x3	General-purpose 3-row inventory. Used by Chest, minecart with chest, ender chest, and barrel
3	minecraft:generic_9x4	A 4-row inventory, not used by the notchian server.
4	minecraft:generic_9x5	A 5-row inventory, not used by the notchian server.
5	minecraft:generic_9x6	General-purpose 6-row inventory, used by large chests.
6	minecraft:generic_3x3	General-purpose 3-by-3 square inventory, used by Dispenser and Dropper
7	minecraft:anvil	Anvil
8	minecraft:beacon	Beacon
9	minecraft:blast_furnace	Blast Furnace
10	minecraft:brewing_stand	Brewing stand
11	minecraft:crafting	Crafting table
12	minecraft:enchantment	Enchantment table
13	minecraft:furnace	Furnace
14	minecraft:grindstone	Grindstone
15	minecraft:hopper	Hopper or minecart with hopper
16	minecraft:lectern	Lectern
17	minecraft:loom	Loom
18	minecraft:merchant	Villager, Wandering Trader
19	minecraft:shulker_box	Shulker box
20	minecraft:legacy_smithing	Smithing Table The Notchian server only sends this type if feature flag update_1_20 was not enabled
21 20	minecraft:smithing	Smithing Table The Notchian server only sends this type if feature flag update_1_20 was enabled
22 21	minecraft:smoker	Smoker
23 22	minecraft:cartography	Cartography Table
24 23	minecraft:stonecutter	Stonecutter

Plugin Channels

No changes so far.

Play

Clientbound

Chunk Data and Update Light

Main article: Chunk Format

See also: #Unload Chunk

	The following information needs to be added to this page:
	How do biomes work now? The biome change happened at the same time as the seed change, but it's not clear how/if biomes could be computed given that it's not the actual seed... (/r/mojira discussion which notes that it seems to be some kind of interpolation)

This packet sends all block entities in the chunk (though sending them is not required; it is still legal to send them with Block Entity Data later). The light data in this packet is the same format as in the Update Light packet.

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x24	Play	Client	Chunk X		Int		Chunk coordinate (block coordinate divided by 16, rounded down)
			Chunk Z		Int		Chunk coordinate (block coordinate divided by 16, rounded down)
			Heightmaps		NBT		Compound containing one long array named MOTION_BLOCKING, which is a heightmap for the highest solid block at each position in the chunk (as a compacted long array with 256 entries, with the number of bits per entry varying depending on the world's height, defined by the formula ceil(log2(height + 1))). The Notchian server also adds a WORLD_SURFACE long array, the purpose of which is unknown, but it's not required for the chunk to be accepted.
			Size		VarInt		Size of Data in bytes
			Data		Byte array		See data structure in Chunk Format
			Number of block entities		VarInt		Number of elements in the following array
			Block Entity	Packed XZ	Array	Byte	The packed section coordinates, calculated from ((blockX & 15) << 4) | (blockZ & 15)
				Y		Short	The height relative to the world
				Type		VarInt	The type of block entity
				Data		NBT	The block entity's data, without the X, Y, and Z values
			Trust Edges		Boolean		If edges should be trusted for light updates.
			Sky Light Mask		BitSet		BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has data in the Sky Light array below. The least significant bit is for blocks 16 blocks to 1 block below the min world height (one section below the world), while the most significant bit covers blocks 1 to 16 blocks above the max world height (one section above the world).
			Block Light Mask		BitSet		BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has data in the Block Light array below. The order of bits is the same as in Sky Light Mask.
			Empty Sky Light Mask		BitSet		BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has all zeros for its Sky Light data. The order of bits is the same as in Sky Light Mask.
			Empty Block Light Mask		BitSet		BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has all zeros for its Block Light data. The order of bits is the same as in Sky Light Mask.
			Sky Light array count		VarInt		Number of entries in the following array; should match the number of bits set in Sky Light Mask
			Sky Light arrays	Length	Array	VarInt	Length of the following array in bytes (always 2048)
				Sky Light array		Array of 2048 bytes	There is 1 array for each bit set to true in the sky light mask, starting with the lowest value. Half a byte per light value. Indexed ((y<<8) | (z<<4) | x) / 2 If there's a remainder, masked 0xF0 else 0x0F.
			Block Light array count		VarInt		Number of entries in the following array; should match the number of bits set in Block Light Mask
			Block Light arrays	Length	Array	VarInt	Length of the following array in bytes (always 2048)
				Block Light array		Array of 2048 bytes	There is 1 array for each bit set to true in the block light mask, starting with the lowest value. Half a byte per light value. Indexed ((y<<8) | (z<<4) | x) / 2 If there's a remainder, masked 0xF0 else 0x0F.

Note that the Notchian client requires an Set Center Chunk packet when it crosses a chunk border, otherwise it'll only display render distance + 2 chunks around the chunk it spawned in.

The compacted array format has been adjusted so that individual entries no longer span across multiple longs, affecting the main data array and heightmaps.

New format, 5 bits per block, containing the following references to blocks in a palette (not shown): 122344566480743131516914101202

0020863148418841 0000000000100000100001100011000101001000010000011000100001000001
01018A7260F68C87 0000000100000001100010100111001001100000111101101000110010000111

Update Light

Updates light levels for a chunk. See Light for information on how lighting works in Minecraft.

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x27	Play	Client	Chunk X		VarInt		Chunk coordinate (block coordinate divided by 16, rounded down)
			Chunk Z		VarInt		Chunk coordinate (block coordinate divided by 16, rounded down)
			Trust Edges		Boolean		If edges should be trusted for light updates.
			Sky Light Mask		BitSet		BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has data in the Sky Light array below. The least significant bit is for blocks 16 blocks to 1 block below the min world height (one section below the world), while the most significant bit covers blocks 1 to 16 blocks above the max world height (one section above the world).
			Block Light Mask		BitSet		BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has data in the Block Light array below. The order of bits is the same as in Sky Light Mask.
			Empty Sky Light Mask		BitSet		BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has all zeros for its Sky Light data. The order of bits is the same as in Sky Light Mask.
			Empty Block Light Mask		BitSet		BitSet containing bits for each section in the world + 2. Each set bit indicates that the corresponding 16×16×16 chunk section has all zeros for its Block Light data. The order of bits is the same as in Sky Light Mask.
			Sky Light array count		VarInt		Number of entries in the following array; should match the number of bits set in Sky Light Mask
			Sky Light arrays	Length	Array	VarInt	Length of the following array in bytes (always 2048)
				Sky Light array		Array of 2048 bytes	There is 1 array for each bit set to true in the sky light mask, starting with the lowest value. Half a byte per light value.
			Block Light array count		VarInt		Number of entries in the following array; should match the number of bits set in Block Light Mask
			Block Light arrays	Length	Array	VarInt	Length of the following array in bytes (always 2048)
				Block Light array		Array of 2048 bytes	There is 1 array for each bit set to true in the block light mask, starting with the lowest value. Half a byte per light value.

A bit will never be set in both the block light mask and the empty block light mask, though it may be present in neither of them (if the block light does not need to be updated for the corresponding chunk section). The same applies to the sky light mask and the empty sky light mask.

Login (play)

See Protocol Encryption for information on logging in.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x28	Play	Client	Entity ID	Int	The player's Entity ID (EID).
			Is hardcore	Boolean
			Gamemode	Unsigned Byte	0: Survival, 1: Creative, 2: Adventure, 3: Spectator.
			Previous Gamemode	Byte	-1: Undefined (null), 0: Survival, 1: Creative, 2: Adventure, 3: Spectator. The previous gamemode. Vanilla client uses this for the debug (F3 + N & F3 + F4) gamemode switch. (More information needed)
			Dimension Count	VarInt	Size of the following array.
			Dimension Names	Array of Identifier	Identifiers for all dimensions on the server.
			Registry Codec	NBT Tag Compound	Represents certain registries that are sent from the server and are applied on the client.
			Dimension Type	Identifier	Name of the dimension type being spawned into.
			Dimension Name	Identifier	Name of the dimension being spawned into.
			Hashed seed	Long	First 8 bytes of the SHA-256 hash of the world's seed. Used client side for biome noise
			Max Players	VarInt	Was once used by the client to draw the player list, but now is ignored.
			View Distance	VarInt	Render distance (2-32).
			Simulation Distance	VarInt	The distance that the client will process specific things, such as entities.
			Reduced Debug Info	Boolean	If true, a Notchian client shows reduced information on the debug screen. For servers in development, this should almost always be false.
			Enable respawn screen	Boolean	Set to false when the doImmediateRespawn gamerule is true.
			Is Debug	Boolean	True if the world is a debug mode world; debug mode worlds cannot be modified and have predefined blocks.
			Is Flat	Boolean	True if the world is a superflat world; flat worlds have different void fog and a horizon at y=0 instead of y=63.
			Has death location	Boolean	If true, then the next two fields are present.
			Death dimension name	Optional Identifier	Name of the dimension the player died in.
			Death location	Optional Position	The location that the player died at.
			Portal cooldown	VarInt	The number of ticks until the player can use the portal againWhat impact does this have on the client? Needs more info.

The Registry Codec NBT Tag Compound (Default value in JSON as of 1.19, 1.19.2) includes three registries: "minecraft:dimension_type", "minecraft:worldgen/biome", and "minecraft:chat_type".

Name	Type	Notes
minecraft:dimension_type	TAG_Compound	The dimension type registry (see below).
minecraft:worldgen/biome	TAG_Compound	The biome registry (see below).
minecraft:chat_type	TAG_Compound	The chat type registry (see below).

Dimension type registry:

Name	Type	Notes
type	TAG_String	The name of the registry. Always "minecraft:dimension_type".
value	TAG_List	List of dimension types registry entries (see below).

Dimension type registry entry:

Name	Type	Notes
name	TAG_String	The name of the dimension type (for example, "minecraft:overworld").
id	TAG_Int	The protocol ID of the dimension (matches the index of the element in the registry list).
element	TAG_Compound	The dimension type (see below).

Dimension type:

Name	Type	Meaning		Values
piglin_safe	TAG_Byte	Whether piglins shake and transform to zombified piglins.		1: true, 0: false.
has_raids	TAG_Byte	Whether players with the Bad Omen effect can cause a raid.		1: true, 0: false.
monster_spawn_light_level	TAG_Int or TAG_Compound	Possibly the light level(s) at which monsters can spawn.	When TAG_Int, 0 - 15. When TAG_Compound, contains the fields: type (TAG_String), appears to be always "minecraft:uniform", and value (TAG_Compound), which contains the fields: max_inclusive (TAG_Int), min_inclusive (TAG_Int).
monster_spawn_block_light_limit	TAG_Int
natural	TAG_Byte	When false, compasses spin randomly. When true, nether portals can spawn zombified piglins.		1: true, 0: false.
ambient_light	TAG_Float	How much light the dimension has.		0.0 to 1.0.
fixed_time	Optional TAG_Long	If set, the time of the day is the specified value.		If set, 0 to 24000.
infiniburn	TAG_String	A resource location defining what block tag to use for infiniburn.		"#" or minecraft resource "#minecraft:...".
respawn_anchor_works	TAG_Byte	Whether players can charge and use respawn anchors.		1: true, 0: false.
has_skylight	TAG_Byte	Whether the dimension has skylight access or not.		1: true, 0: false.
bed_works	TAG_Byte	Whether players can use a bed to sleep.		1: true, 0: false.
effects	TAG_String	?		"minecraft:overworld", "minecraft:the_nether", "minecraft:the_end" or something else.
min_y	TAG_Int	The minimum Y level.		A multiple of 16. Example: -64
height	TAG_Int	The maximum height.		A multiple of 16. Example: 256
logical_height	TAG_Int	The maximum height to which chorus fruits and nether portals can bring players within this dimension.		0-384.
coordinate_scale	TAG_Double	The multiplier applied to coordinates when traveling to the dimension.		0.00001 - 30000000.0
ultrawarm	TAG_Byte	Whether the dimensions behaves like the nether (water evaporates and sponges dry) or not. Also causes lava to spread thinner.		1: true, 0: false.
has_ceiling	TAG_Byte	Whether the dimension has a bedrock ceiling or not. When true, causes lava to spread faster.		1: true, 0: false.

Biome registry:

Name	Type	Notes
type	TAG_String	The name of the registry. Always "minecraft:worldgen/biome".
value	TAG_List	List of biome registry entries (see below).

Biome registry entry:

Name	Type	Notes
name	TAG_String	The name of the biome (for example, "minecraft:ocean").
id	TAG_Int	The protocol ID of the biome (matches the index of the element in the registry list).
element	TAG_Compound	The biome properties (see below).

Biome properties:

Name			Type		Meaning		Values
precipitation			TAG_String		The type of precipitation in the biome.		"rain", "snow", or "none".
depth			Optional TAG_Float		The depth factor of the biome.		The default values vary between 1.5 and -1.8.
temperature			TAG_Float		The temperature factor of the biome.		The default values vary between 2.0 and -0.5.
scale			Optional TAG_Float		?		The default values vary between 1.225 and 0.0.
downfall			TAG_Float		?		The default values vary between 1.0 and 0.0.
category			Optional TAG_String		The category of the biome.		Known values are "ocean", "plains", "desert", "forest", "extreme_hills", "taiga", "swamp", "river", "nether", "the_end", "icy", "mushroom", "beach", "jungle", "mesa", "savanna", and "none".
temperature_modifier			Optional TAG_String		?		The only known value is "frozen".
effects	sky_color		TAG_Compound	TAG_Int	The color of the sky.		Example: 8364543, which is #7FA1FF in RGB.
	water_fog_color			TAG_Int	Possibly the tint color when swimming.		Example: 8364543, which is #7FA1FF in RGB.
	fog_color			TAG_Int	Possibly the color of the fog effect when looking past the view distance.		Example: 8364543, which is #7FA1FF in RGB.
	water_color			TAG_Int	The tint color of the water blocks.		Example: 8364543, which is #7FA1FF in RGB.
	foliage_color			Optional TAG_Int	The tint color of the grass.		Example: 8364543, which is #7FA1FF in RGB.
	grass_color			Optional TAG_Int	?		Example: 8364543, which is #7FA1FF in RGB.
	grass_color_modifier			Optional TAG_String	Unknown, likely affects foliage color.		If set, known values are "swamp" and "dark_forest".
	music			Optional TAG_Compound	Music properties for the biome.		If present, contains the fields: replace_current_music (TAG_Byte), sound (TAG_String), max_delay (TAG_Int), min_delay (TAG_Int).
	ambient_sound			Optional TAG_String	Ambient soundtrack.		If present, the ID of a soundtrack. Example: "minecraft:ambient.basalt_deltas.loop".
	additions_sound			Optional TAG_Compound	Additional ambient sound that plays randomly.		If present, contains the fields: sound (TAG_String), tick_chance (TAG_Double).
	mood_sound			Optional TAG_Compound	Additional ambient sound that plays at an interval.		If present, contains the fields: sound (TAG_String), tick_delay (TAG_Int), offset (TAG_Double), block_search_extent (TAG_Int).
	particle	probability	Optional TAG_Compound	TAG_FLOAT	Particles that appear randomly in the biome.	Possibly the probability of spawning the particle.	?
		options		TAG_COMPOUND		The properties of the particle to spawn.	Contains the field "type" (TAG_String), which identifies the particle type.

Chat registry:

Name	Type	Notes
type	TAG_String	The name of the registry. Always "minecraft:chat_type".
value	TAG_List	List of chat type registry entries (see below).

Chat type:

Name	Type	Notes
name	TAG_String	The type's name (eg "minecraft:chat")
id	TAG_Int
elements	TAG_Compound	"chat" and "narration" TAG_Compound's (see below)

Chat type "chat" and "narration":

Name	Type	Notes
translation_key	TAG_String
style	TAG_Compound	Similar to Chat JSON (only present in "chat" TAG_Compound)
parameters	TAG_List of TAG_String	Values can be "sender", "target" and "content"

Open Sign Editor

Sent when the client has placed a sign and is allowed to send Update Sign. There must already be a sign at the given location (which the client does not do automatically) - send a Block Update first.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x31	Play	Client	Location	Position
			Is Front Text	Boolean	Whether the opened editor is for the front or on the back of the sign

End Combat

Unused by the Notchian client. This data was once used for twitch.tv metadata circa 1.8.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x36	Play	Client	Duration	VarInt	Length of the combat in ticks.
			Entity ID	Int	ID of the primary opponent of the ended combat, or -1 if there is no obvious primary opponent.

Combat Death

Used to send a respawn screen.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x38	Play	Client	Player ID	VarInt	Entity ID of the player that died (should match the client's entity ID).
			Entity ID	Int	The killer entity's ID, or -1 if there is no obvious killer.
			Message	Chat	The death message.

Respawn

To change the player's dimension (overworld/nether/end), send them a respawn packet with the appropriate dimension, followed by prechunks/chunks for the new dimension, and finally a position and look packet. You do not need to unload chunks, the client will do it automatically.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x41	Play	Client	Dimension Type	Identifier	Valid dimensions are defined per dimension registry sent in Login (play)
			Dimension Name	Identifier	Name of the dimension being spawned into.
			Hashed seed	Long	First 8 bytes of the SHA-256 hash of the world's seed. Used client side for biome noise
			Gamemode	Unsigned Byte	0: Survival, 1: Creative, 2: Adventure, 3: Spectator.
			Previous Gamemode	Byte	-1: Undefined (null), 0: Survival, 1: Creative, 2: Adventure, 3: Spectator. The previous gamemode. Vanilla client uses this for the debug (F3 + N & F3 + F4) gamemode switch. (More information needed)
			Is Debug	Boolean	True if the world is a debug mode world; debug mode worlds cannot be modified and have predefined blocks.
			Is Flat	Boolean	True if the world is a superflat world; flat worlds have different void fog and a horizon at y=0 instead of y=63.
			Data kept	Byte	Bit mask. 0x01: Keep attributes, 0x02: Keep metadata. Tells which data should be kept on the client side once the player has respawned. In the Notchian implementation, this is context dependent: normal respawns (after death) keep no data; exiting the end poem/credits keeps the attributes; other dimension changes (portals or teleports) keep all data.
			Has death location	Boolean	If true, then the next two fields are present.
			Death dimension Name	Optional Identifier	Name of the dimension the player died in.
			Death location	Optional Position	The location that the player died at.
			Portal cooldown	VarInt	The number of ticks until the player can use the portal againWhat impact does this have on the client? Needs more info.

Avoid changing player's dimension to same dimension they were already in unless they are dead. If you change the dimension to one they are already in, weird bugs can occur, such as the player being unable to attack other players in new world (until they die and respawn).

Before 1.16, if you must respawn a player in the same dimension without killing them, send two respawn packets, one to a different world and then another to the world you want. You do not need to complete the first respawn; it only matters that you send two packets.

Update Section Blocks

Fired whenever 2 or more blocks are changed within the same chunk on the same tick.

Changing blocks in chunks not loaded by the client is unsafe (see note on Block Update).

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x43	Play	Client	Chunk section position	Long	Chunk section coordinate (encoded chunk x and z with each 22 bits, and section y with 20 bits, from left to right).
			Suppress Light Updates	Boolean	Whether to ignore light updates caused by the contained changes. Always inverse the preceding Update Light packet's "Trust Edges" bool
			Blocks array size	VarInt	Number of elements in the following array.
			Blocks	Array of VarLong	Each entry is composed of the block state id, shifted left by 12, and the relative block position in the chunk section (4 bits for x, z, and y, from left to right).

Chunk section position is encoded:

((sectionX & 0x3FFFFF) << 42) | (sectionY & 0xFFFFF) | ((sectionZ & 0x3FFFFF) << 20);

and decoded:

sectionX = long >> 42;
sectionY = long << 44 >> 44;
sectionZ = long << 22 >> 42;

Blocks are encoded:

blockStateId << 12 | (blockLocalX << 8 | blockLocalZ << 4 | blockLocalY)
//Uses the local position of the given block position relative to its respective chunk section

Update Advancements

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x69	Play	Client	Reset/Clear		Boolean		Whether to reset/clear the current advancements.
			Mapping size		VarInt		Size of the following array.
			Advancement mapping	Key	Array	Identifier	The identifier of the advancement.
				Value		Advancement	See below
			List size		VarInt		Size of the following array.
			Identifiers		Array of Identifier		The identifiers of the advancements that should be removed.
			Progress size		VarInt		Size of the following array.
			Progress mapping	Key	Array	Identifier	The identifier of the advancement.
				Value		Advancement progress	See below.

Advancement structure:

Field Name		Field Type		Notes
Has parent		Boolean		Indicates whether the next field exists.
Parent id		Optional Identifier		The identifier of the parent advancement.
Has display		Boolean		Indicates whether the next field exists.
Display data		Optional advancement display		See below.
Number of criteria		VarInt		Size of the following array.
Criteria	Key	Array	Identifier	The identifier of the criterion.
	Value		Void	There is no content written here. Perhaps this will be expanded in the future?
Array length		VarInt		Number of arrays in the following array.
Requirements	Array length 2	Array	VarInt	Number of elements in the following array.
	Requirement		Array of String	Array of required criteria.
Sends telemetry data		Boolean		Whether the client should include this achievement in the telemetry data when it's completed. The Notchian client only sends data for advancements on the minecraft namespace.

Advancement display:

Field Name	Field Type	Notes
Title	Chat
Description	Chat
Icon	Slot
Frame type	VarInt Enum	0 = task, 1 = challenge, 2 = goal.
Flags	Int	0x01: has background texture; 0x02: show_toast; 0x04: hidden.
Background texture	Optional Identifier	Background texture location. Only if flags indicates it.
X coord	Float
Y coord	Float

Advancement progress:

Field Name		Field Type		Notes
Size		VarInt		Size of the following array.
Criteria	Criterion identifier	Array	Identifier	The identifier of the criterion.
	Criterion progress		Criterion progress

Criterion progress:

Field Name	Field Type	Notes
Achieved	Boolean	If true, next field is present.
Date of achieving	Optional Long	As returned by Date.getTime.

Feature Flags

Used to enable and disable features, generally experimental ones, on the client.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x6B	Play	Client	Total Features	VarInt	Number of features that appear in the array below.
			Feature Flags	Identifier Array

As of 1.19.4 1.20, the following feature flags are available:

• minecraft:vanilla - enables vanilla features
• minecraft:bundle - enables support for the bundle
• minecraft:update_1_20 - enables all the Minecraft 1.20 features that are available in 1.19.4

Update Recipes

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x6D	Play	Client	Num Recipes		VarInt		Number of elements in the following array.
			Recipe	Type	Array	Identifier	The recipe type, see below.
				Recipe ID		Identifier
				Data		Varies	Additional data for the recipe.

Recipe types:

Type	Description	Data
minecraft:crafting_shapeless	Shapeless crafting recipe. All items in the ingredient list must be present, but in any order/slot.	As follows: Name Type Description Group String Used to group similar recipes together in the recipe book. Tag is present in recipe JSON. Category VarInt Enum Building = 0, Redstone = 1, Equipment = 2, Misc = 3 Ingredient count VarInt Number of elements in the following array. Ingredients Array of Ingredient. Result Slot
minecraft:crafting_shaped	Shaped crafting recipe. All items must be present in the same pattern (which may be flipped horizontally or translated).	As follows: Name Type Description Width VarInt Height VarInt Group String Used to group similar recipes together in the recipe book. Tag is present in recipe JSON. Category VarInt Enum Building = 0, Redstone = 1, Equipment = 2, Misc = 3 Ingredients Array of Ingredient Length is width * height. Indexed by x + (y * width). Result Slot Show notification Boolean Show a toast when the recipe is added.
minecraft:crafting_special_armordye	Recipe for dying leather armor	As follows: Name Type Description Category VarInt Enum Building = 0, Redstone = 1, Equipment = 2, Misc = 3
minecraft:crafting_special_bookcloning	Recipe for copying contents of written books
minecraft:crafting_special_mapcloning	Recipe for copying maps
minecraft:crafting_special_mapextending	Recipe for adding paper to maps
minecraft:crafting_special_firework_rocket	Recipe for making firework rockets
minecraft:crafting_special_firework_star	Recipe for making firework stars
minecraft:crafting_special_firework_star_fade	Recipe for making firework stars fade between multiple colors
minecraft:crafting_special_repairitem	Recipe for repairing items via crafting
minecraft:crafting_special_tippedarrow	Recipe for crafting tipped arrows
minecraft:crafting_special_bannerduplicate	Recipe for copying banner patterns
minecraft:crafting_special_shielddecoration	Recipe for applying a banner's pattern to a shield
minecraft:crafting_special_shulkerboxcoloring	Recipe for recoloring a shulker box
minecraft:crafting_special_suspiciousstew	Recipe for crafting suspicious stews
minecraft:crafting_decorated_pot	Recipe for crafting decorated pots The Notchian server only sends this recipe if feature flag update_1_20 was enabled
minecraft:smelting	Smelting recipe	As follows: Name Type Description Group String Used to group similar recipes together in the recipe book. Category VarInt Enum Food = 0, Blocks = 1, Misc = 2 Ingredient Ingredient Result Slot Experience Float Cooking time VarInt
minecraft:blasting	Blast furnace recipe
minecraft:smoking	Smoker recipe
minecraft:campfire_cooking	Campfire recipe
minecraft:stonecutting	Stonecutter recipe	As follows: Name Type Description Group String Used to group similar recipes together in the recipe book. Tag is present in recipe JSON. Ingredient Ingredient Result Slot
minecraft:smithing	Smithing table recipe The Notchian server only sends this recipe if feature flag update_1_20 was not enabled	As follows: Name Type Description Base Ingredient First item. Addition Ingredient Second item. Result Slot
minecraft:smithing_transform	Recipe for smithing netherite gear The Notchian server only sends this recipe if feature flag update_1_20 was enabled. It supersedes the minecraft:smithing recipe type	As follows: Name Type Description Template Ingredient The smithing template. Base Ingredient The base item. Addition Ingredient The additional ingredient. Result Slot
minecraft:smithing_trim	Recipe for applying armor trims The Notchian server only sends this recipe if feature flag update_1_20 was enabled. It supersedes the minecraft:smithing recipe type	As follows: Name Type Description Template Ingredient The smithing template. Base Ingredient The base item. Addition Ingredient The additional ingredient.

Ingredient is defined as:

Name	Type	Description
Count	VarInt	Number of elements in the following array.
Items	Array of Slot	Any item in this array may be used for the recipe. The count of each item should be 1.

Serverbound

Update Sign

This message is sent from the client to the server when the “Done” button is pushed after placing a sign.

The server only accepts this packet after Open Sign Editor, otherwise this packet is silently ignored.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x2E	Play	Server	Location	Position	Block Coordinates.
			Is Front Text	Boolean	Whether the updated text is in front or on the back of the sign
			Line 1	String (384)	First line of text in the sign.
			Line 2	String (384)	Second line of text in the sign.
			Line 3	String (384)	Third line of text in the sign.
			Line 4	String (384)	Fourth line of text in the sign.

Status

Clientbound

No changes so far.

Serverbound

No changes so far.

Login

Clientbound

No changes so far.

Serverbound

No changes so far.