Pre-release protocol

Revision as of 23:29, 12 February 2012 by Sadimusi (talk | contribs) (→‎Client to Server: Added further info to modified handshake)
Jump to navigation Jump to search

This page documents the changes from the last stable Minecraft release (currently 1.1) to the current pre-release (currently 12w03a)

New packets

Entity Head Look (0x23)

Changes the direction an entity's head is facing.

Packet ID Field Name Field Type Example Notes
0x23 Entity ID int
Head Yaw byte Head yaw in steps of 2π/256
Total Size: 6 bytes

Update Tile Entity (0x84)

Essentially a block update on a tile entity.

Packet ID Field Name Field Type Example Notes
0x84 X int
Y short
Z int
Action byte The type of update to perform
Custom 1 int Varies
Custom 2 int Varies
Custom 3 int Varies
Total Size: 24 bytes


  • 1: Set mob displayed inside a mob spawner. Custom 1 contains the mob type

Changed packets

Handshake (0x02)

Client to Server

The hostname and port were added to this packet, most likely to allow virtual hosting .(sample implementation)

Packet ID Field Name Field Type Example Notes
0x02 UsernameAndHost string TkTech;localhost:25565 The username of the player attempting to connect, and the host he is connecting to, seperated by a semicolon.
Total Size: 3 bytes + length of strings

Mob Spawn (0x18)

New byte field: head yaw

This needs confirmation!

Packet ID Field Name Field Type Example Notes
0x18 EID int 446 Entity ID
Type byte 91 The type of mob. See Entities#Mobs
X int 13366 The Absolute Integer X Position of the object
Y int 2176 The Absolute Integer Y Position of the object
Z int 1680 The Absolute Integer Z Position of the object
Yaw byte -27 The yaw in steps of 2π/256
Pitch byte 0 The pitch in steps of 2π/256
Head Yaw byte Head yaw in steps of 2π/256
Metadata Metadata 127 Varies by mob, see Entities
Total Size: 21 bytes + Metadata (at least 1)

Other changes

Protocol version is now 25.

Protocol History


  • 12w06a
  • Protocol version is now 25
  • New packet: 0x84


  • 12w04a
  • Protocol version has not been changed
  • Handshake Packet by client (0x02) now contains the server host and port
  • Window Open Packet (0x64): WindowTitle is now longer than accepted by older clients. Contains a keyword such as "container.furnace"


  • 12w03a
  • Protocol version is now 24
  • New packet: 0x23
  • MobSpawn: new field, 1 byte inserted before metadata.