Pre-release protocol

This page documents the changes from the last stable Minecraft release (currently 1.11.2, protocol 316) to the current pre-release (currently 17w13b, protocol 319). 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
Handshaking serverbound
0x00	Handshake	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
Play clientbound
0x08	Advancements	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x08}}{{#if:0x09|{{#if:0x08| }}0x09}}	Block Break Animation	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x09}}{{#if:0x0A|{{#if:0x09| }}0x0A}}	Update Block Entity	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x0A}}{{#if:0x0B|{{#if:0x0A| }}0x0B}}	Block Action	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x0B}}{{#if:0x0C|{{#if:0x0B| }}0x0C}}	Block Change	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x0C}}{{#if:0x0D|{{#if:0x0C| }}0x0D}}	Boss Bar	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x0D}}{{#if:0x0E|{{#if:0x0D| }}0x0E}}	Server Difficulty	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x0E}}{{#if:0x0F|{{#if:0x0E| }}0x0F}}	Tab-Complete (clientbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x0F}}{{#if:0x10|{{#if:0x0F| }}0x10}}	Chat Message (clientbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x10}}{{#if:0x11|{{#if:0x10| }}0x11}}	Multi Block Change	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x11}}{{#if:0x12|{{#if:0x11| }}0x12}}	Confirm Transation (clientbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x12}}{{#if:0x13|{{#if:0x12| }}0x13}}	Close Window (clientbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x13}}{{#if:0x14|{{#if:0x13| }}0x14}}	Open Window	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x14}}{{#if:0x15|{{#if:0x14| }}0x15}}	Window Items	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x15}}{{#if:0x16|{{#if:0x15| }}0x16}}	Window Property	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x16}}{{#if:0x17|{{#if:0x16| }}0x17}}	Set Slot	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x17}}{{#if:0x18|{{#if:0x17| }}0x18}}	Set Cooldown	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x18}}{{#if:0x19|{{#if:0x18| }}0x19}}	Plugin Message (clientbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x19}}{{#if:0x1A|{{#if:0x19| }}0x1A}}	Named Sound Effect	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x1A}}{{#if:0x1B|{{#if:0x1A| }}0x1B}}	Disconnect (play)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x1B}}{{#if:0x1C|{{#if:0x1B| }}0x1C}}	Entity Status	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x1C}}{{#if:0x1D|{{#if:0x1C| }}0x1D}}	Explosion	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x1D}}{{#if:0x1E|{{#if:0x1D| }}0x1E}}	Unload Chunk	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x1E}}{{#if:0x1F|{{#if:0x1E| }}0x1F}}	Change Game State	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x1F}}{{#if:0x20|{{#if:0x1F| }}0x20}}	Keep Alive (clientbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x20}}{{#if:0x21|{{#if:0x20| }}0x21}}	Chunk Data	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x21}}{{#if:0x22|{{#if:0x21| }}0x22}}	Effect	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x22}}{{#if:0x23|{{#if:0x22| }}0x23}}	Particle	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x23}}{{#if:0x24|{{#if:0x23| }}0x24}}	Join Game	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x24}}{{#if:0x25|{{#if:0x24| }}0x25}}	Particle	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x25}}{{#if:0x26|{{#if:0x25| }}0x26}}	Entity Relative Move	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x26}}{{#if:0x27|{{#if:0x26| }}0x27}}	Entity Look And Relative Move	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x27}}{{#if:0x28|{{#if:0x27| }}0x28}}	Entity Look	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x28}}{{#if:0x29|{{#if:0x28| }}0x29}}	Entity	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x29}}{{#if:0x2A|{{#if:0x29| }}0x2A}}	Vehicle Move (clientbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x2A}}{{#if:0x2B|{{#if:0x2A| }}0x2B}}	Open Sign Editor	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x2B}}{{#if:0x2C|{{#if:0x2B| }}0x2C}}	Player Abilities (clientbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x2C}}{{#if:0x2D|{{#if:0x2C| }}0x2D}}	Combat Event	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x2D}}{{#if:0x2E|{{#if:0x2D| }}0x2E}}	Player List Item	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x2E}}{{#if:0x2F|{{#if:0x2E| }}0x2F}}	Player Position And Look (clientbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x2F}}{{#if:0x30|{{#if:0x2F| }}0x30}}	Use Bed	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x31	Unlock Recipe	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x30}}{{#if:0x32|{{#if:0x30| }}0x32}}	Destroy Entities	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x31}}{{#if:0x33|{{#if:0x31| }}0x33}}	Remove Entity Effect	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x32}}{{#if:0x34|{{#if:0x32| }}0x34}}	Resource Pack Send	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x33}}{{#if:0x35|{{#if:0x33| }}0x35}}	Respawn	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x34}}{{#if:0x36|{{#if:0x34| }}0x36}}	Entity Head Look	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x35}}{{#if:0x37|{{#if:0x35| }}0x37}}	World Border	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x36}}{{#if:0x38|{{#if:0x36| }}0x38}}	Camera	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x37}}{{#if:0x39|{{#if:0x37| }}0x39}}	Held Item Change (clientbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x38}}{{#if:0x3A|{{#if:0x38| }}0x3A}}	Display Scoreboard	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x39}}{{#if:0x3B|{{#if:0x39| }}0x3B}}	Entity Metadata	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x3A}}{{#if:0x3C|{{#if:0x3A| }}0x3C}}	Attach Entity	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x3B}}{{#if:0x3D|{{#if:0x3B| }}0x3D}}	Entity Velocity	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x3C}}{{#if:0x3E|{{#if:0x3C| }}0x3E}}	Entity Equipment	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x3D}}{{#if:0x3F|{{#if:0x3D| }}0x3F}}	Set Experience	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x3E}}{{#if:0x40|{{#if:0x3E| }}0x40}}	Update Health	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x3F}}{{#if:0x41|{{#if:0x3F| }}0x41}}	Scoreboard Objective	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x40}}{{#if:0x42|{{#if:0x40| }}0x42}}	Set Passengers	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x41}}{{#if:0x43|{{#if:0x41| }}0x43}}	Teams	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x42}}{{#if:0x44|{{#if:0x42| }}0x44}}	Update Score	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x43}}{{#if:0x45|{{#if:0x43| }}0x45}}	Spawn Position	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x44}}{{#if:0x46|{{#if:0x44| }}0x46}}	Time Update	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x45}}{{#if:0x47|{{#if:0x45| }}0x47}}	Title	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x46}}{{#if:0x48|{{#if:0x46| }}0x48}}	Sound Effect	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x47}}{{#if:0x49|{{#if:0x47| }}0x49}}	Player List Header And Footer	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x48}}{{#if:0x4A|{{#if:0x48| }}0x4A}}	Collect Item	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x49}}{{#if:0x4B|{{#if:0x49| }}0x4B}}	Entity Teleport	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x4A}}{{#if:0x4C|{{#if:0x4A| }}0x4C}}	Entity Properties	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x4B}}{{#if:0x4D|{{#if:0x4B| }}0x4D}}	Entity Effect	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
Play serverbound
0x01	Unknown	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x01}}{{#if:0x02|{{#if:0x01| }}0x02}}	Tab-Complete (serverbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x02}}{{#if:0x03|{{#if:0x02| }}0x03}}	Chat Message (serverbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x03}}{{#if:0x04|{{#if:0x03| }}0x04}}	Client Status	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x04}}{{#if:0x05|{{#if:0x04| }}0x05}}	Client Settings	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x05}}{{#if:0x06|{{#if:0x05| }}0x06}}	Confirm Transaction (serverbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x06}}{{#if:0x07|{{#if:0x06| }}0x07}}	Enchant Item	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x07}}{{#if:0x08|{{#if:0x07| }}0x08}}	Click Window	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x08}}{{#if:0x09|{{#if:0x08| }}0x09}}	Close Window (serverbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x09}}{{#if:0x0A|{{#if:0x09| }}0x0A}}	Plugin Message (serverbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x0A}}{{#if:0x0B|{{#if:0x0A| }}0x0B}}	Use Entity	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x0B}}{{#if:0x0C|{{#if:0x0B| }}0x0C}}	Keep Alive (serverbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x0C}}{{#if:0x0D|{{#if:0x0C| }}0x0D}}	Player Position	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x0D}}{{#if:0x0E|{{#if:0x0D| }}0x0E}}	Player Position And Look (serverbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x0E}}{{#if:0x0F|{{#if:0x0E| }}0x0F}}	Player Look	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x0F}}{{#if:0x10|{{#if:0x0F| }}0x10}}	Player	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x10}}{{#if:0x11|{{#if:0x10| }}0x11}}	Vehicle Move (serverbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x11}}{{#if:0x12|{{#if:0x11| }}0x12}}	Steer Boat	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x12}}{{#if:0x13|{{#if:0x12| }}0x13}}	Player Abilities (serverbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x13}}{{#if:0x14|{{#if:0x13| }}0x14}}	Player Digging	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x14}}{{#if:0x15|{{#if:0x14| }}0x15}}	Entity Action	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x15}}{{#if:0x16|{{#if:0x15| }}0x16}}	Steer Vehicle	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x17	Recipe Displayed	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x16}}{{#if:0x18|{{#if:0x16| }}0x18}}	Resource Pack Status	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x17}}{{#if:0x19|{{#if:0x17| }}0x19}}	Held Item Change (serverbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x18}}{{#if:0x1A|{{#if:0x18| }}0x1A}}	Creative Inventory Action	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x19}}{{#if:0x1B|{{#if:0x19| }}0x1B}}	Update Sign	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x1A}}{{#if:0x1C|{{#if:0x1A| }}0x1C}}	Animation (serverbound)	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x1B}}{{#if:0x1D|{{#if:0x1B| }}0x1D}}	Spectate	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x1C}}{{#if:0x1E|{{#if:0x1C| }}0x1E}}	Player Block Placement	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}
0x1D}}{{#if:0x1F|{{#if:0x1D| }}0x1F}}	Use Item	added	Current }}	removed	unchanged | (unchanged) | Pre }} }}

New/modified data types

Entity Metadata

Note that entity metadata is a totally distinct concept from block metadata. It is not required to send all metadata fields, or even any metadata fields, so long as the terminating entry is correctly sent.

Entity Metadata is an array of entries, each of which looks like the following:

Name	Type	Meaning
Index	Unsigned Byte	Unique index key determining the meaning of the following value, see the table below. If this is 0xff then the it is the end of the Entity Metadata array and no more is read.
Type	Optional Byte Enum	Only if Index is not 0xff; the type of the index, see the table below
Value	Optional value of Type	Only if Index is not 0xff: the value of the metadata field

Value of Type field	Type of Value field	Notes
0	Byte
1	VarInt
2	Float
3	String
4	Chat
5	Slot
6	Boolean
7	Rotation	3 floats: rotation on x, rotation on y, rotation on z
8	Position
9	OptPosition (Boolean + Optional Position)	Position is present if the Boolean is set to true
10	Direction (VarInt)	(Down = 0, Up = 1, North = 2, South = 3, West = 4, East = 5)
11	OptUUID (Boolean + Optional UUID)	UUID is present if the Boolean is set to true
12	OptBlockID (VarInt)	0 for absent otherwise, id << 4 | data
13	NBT Tag

Entity classes also recursively inherit fields from classes they extend.

Parrot

Extends TameableAnimal.

Index	Type	Meaning		Default
15	VarInt	Variant (0: red/blue, 1: blue, 2: green, 3: yellow/blue)		0

Player

Extends Living.

Index	Type	Meaning		Default
11	Float	Additional Hearts		0.0
12	VarInt	Score		0
13	Byte	The Displayed Skin Parts bit mask that is sent in Client Settings		0
		Bit mask	Meaning
		0x01	Cape enabled
		0x02	Jacket enabled
		0x04	Left sleeve enabled
		0x08	Right sleeve enabled
		0x10	Left pants leg enabled
		0x20	Right pants leg enabled
		0x40	Hat enabled
		0x80	Unused
14	Byte	Main hand (0 : Left, 1 : Right)		1
15	NBT Tag	Left shoulder entity data
16	NBT Tag	Right shoulder entity data

Block Actions

No changes so far.

Plugin Channels

No changes so far.

Play

Clientbound

Advancements

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x08	Play	Client	Mapping size		VarInt		Size of the following array
			Advancement mapping	Key	Array	Identifier	minecraft:something-style identifier - What does this identify?
				Value		Advancement	See below
			VarInt		List size		Size of the following array
			Identifiers		Array of Identifier		Unclear what the point of this is
			VarInt		Progress size		Size of the following array
			Progress mapping	Key	Array	Identifier	minecraft:something-style identifier - What does this identify?
				Value		Advancement progress	See below

Advancement structure:

Field Name		Field Type		Notes
Flag 1		Boolean		Indicates whether the next field exists
Unknown		Optional Identifier
Flag 2		Boolean		Indicates whether the next field exists
Unknown		Optional advancement display		See below.
Number of criteria		VarInt		Size of the following array
Criteria	Key	Array	Identifier	Not sure what is identified
	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
?	Array length 2	Array	VarInt	Number of elements in the following array
	?		Array of String

Advancement display:

Field Name	Field Type	Notes
Title	Chat
Unknown	VarInt	May be displayed item ID. When 0, indicates null
Frame type	VarInt enum	0 = TASK, 1 = CHALLENGE
Flag	Boolean	Indicates whether the next field exists
Identifier	Optional Identifier	Background texture?
Unknown	VarInt	X coord?
Unknown	INVALID (VarInt when writing, Int when reading)	Y coord?

Advancement progress:

Field Name		Field Type		Notes
Size		VarInt		Size of the following array
Criteria	Criterion identifier	Array	Identifier	Probably the same as delared earlier
	Criterion progress		Criterion progress

Criterion progress:

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

Unlock Recipe

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x31	Play	Client
			Array size		VarInt		Number of elements in the following array
			Recipes	Identifier	Array	Identifier
				?		Boolean
				?		Boolean

Serverbound

Unknown

Packet ID	State	Bound To	Field Name		Field Type		Notes
0x01	Play	Server	?		Byte
			?		Short
			?		Boolean
			Array size		Byte		Number of elements in the following array
			?	Partial identifier	Array	String (64)	The portion of an identifier after "minecraft:", or empty if not present
				?		Short
				?		Byte
				?		Byte

Recipe displayed

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x17	Play	Server	Identifier	Identifier
			Param	Int

Handshaking

Clientbound

No changes so far.

Serverbound

No changes so far.

Handshake

This causes the server to switch into the target state.

Packet ID	State	Bound To	Field Name	Field Type	Notes
0x00	Handshaking	Server	Protocol Version	VarInt	See protocol version numbers (currently {{#if:316|316}}{{#if:319|{{#if:316| }}319}})
			Server Address	String	Hostname or IP, e.g. localhost or 127.0.0.1, that was used to connect. The Notchian server does not use this information.
			Server Port	Unsigned Short	Default is 25565. The Notchian server does not use this information.
			Next State	VarInt Enum	1 for status, 2 for login

Status

Clientbound

No changes so far.

Serverbound

No changes so far.

Login

Clientbound

No changes so far.

Serverbound

No changes so far.