Pre-release protocol
This page documents the changes from the last stable Minecraft release (currently 1.8.8, protocol 47) to the current pre-release (currently 15w31a, protocol 49). 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.
Protocol history
None so far.
New/modified data types
None so far.
Handshaking
Clientbound
No changes so far.
Serverbound
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 |
| Server Address | String | hostname or IP, e.g. localhost or 127.0.0.1 | |||
| Server Port | Unsigned Short | default is 25565 | |||
| Next State | VarInt | 1 for status, 2 for login |
Play
Clientbound
No changes so far.
Serverbound
Player Digging
Sent when the player mines a block. A Notchian server only accepts digging packets with coordinates within a 6-unit radius of the player's position.
| Packet ID | State | Bound To | Field Name | Field Type | Notes |
|---|---|---|---|---|---|
| 0x07 | Play | Server | Status | Byte | The action the player is taking against the block (see below) |
| Location | Position | Block position | |||
| Face | Byte | The face being hit (see below) |
Status can (currently) be one of six values:
| Meaning | Value |
|---|---|
| Started digging | 0
|
| Cancelled digging | 1
|
| Finished digging | 2
|
| Drop item stack | 3
|
| Drop item | 4
|
| Shoot arrow / finish eating | 5
|
| Swap item in Hand | 6
|
Notchian clients send a 0 (started digging) when they start digging and a 2 (finished digging) once they think they are finished. If digging is aborted, the client simply send a 1 (cancel digging).
Status code 4 (drop item) is a special case. In-game, when you use the Drop Item command (keypress 'q'), a dig packet with a status of 4, and all other values set to 0, is sent from client to server. Status code 3 is similar, but drops the entire stack.
Status code 5 (shoot arrow / finish eating) is also a special case. The x, y and z fields are all set to 0 like above, with the exception of the face field, which is set to 255.
Status code 6 is another special case. Used to swap or assign an item to the second hand. The rest of the fields (x, y, z and face) are all set to 0.
The face can be one of six values, representing the face being hit:
| Value | 0 | 1 | 2 | 3 | 4 | 5 |
|---|---|---|---|---|---|---|
| Offset | -Y | +Y | -Z | +Z | -X | +X |
Held Item Change
Sent when the player changes the slot selection
| Packet ID | State | Bound To | Field Name | Field Type | Notes |
|---|---|---|---|---|---|
| Play | Server | Slot | Short | The slot which the player has selected (0–8) |
Animation
Sent when the player's arm swings
| Packet ID | State | Bound To | Field Name | Field Type | Notes |
|---|---|---|---|---|---|
| Play | Server | Hand | Byte | Hand used for the animation. |
Entity Action
Sent at least when crouching, leaving a bed, or sprinting. To send action animation to client use 0x28. The client will send this with Action ID = 3 when “Leave Bed” is clicked.
| Packet ID | State | Bound To | Field Name | Field Type | Notes |
|---|---|---|---|---|---|
| Play | Server | Entity ID | VarInt | Player ID | |
| Action ID | VarInt | The ID of the action, see below | |||
| Jump Boost | VarInt | Horse jump boost. Ranged from 0 -> 100. |
Action ID can be one of the following values:
| ID | Action |
|---|---|
| 0 | Crouch |
| 1 | Uncrouch |
| 2 | Leave bed |
| 3 | Start sprinting |
| 4 | Stop sprinting |
| 5 | Jump with horse |
Steer Vehicle
| Packet ID | State | Bound To | Field Name | Field Type | Notes |
|---|---|---|---|---|---|
| Play | Server | Sideways | Float | Positive to the left of the player | |
| Forward | Float | Positive forward | |||
| Flags | Unsigned Byte | Bit mask. 0x1: jump, 0x2: unmount |
Status
Clientbound
No changes so far.
Serverbound
No changes so far.
Login
Clientbound
No changes so far.
Serverbound
No changes so far.
