Pre-release protocol

Revision as of 05:40, 20 December 2012 by Ammaraskar (talk | contribs) (Fix packet id)
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This page documents the changes from the last stable Minecraft release (currently 1.4.5, protocol 49) to the current pre-release (or weekly release). Note that this page contains bleeding-edge information that may not be completely or correctly documented.

New Packets


Changed Packets

Held Item Change (0x10)


Packet ID Field Name Field Type Example Notes
0x10 Slot ID short 1 The slot which the player has selected (0-8)
Total Size: 3 bytes

This packet is now bidirectional.

Changed Data Types

Spawn Object/Vehicle (0x17)

Server to Client

Packet ID Field Name Field Type Example Notes
0x17 EID int 62 Entity ID of the Object
Type byte 11 The type of object (see Entities#Objects)
X int 16080 The Absolute Integer X Position of the object
Y int 2299 The Absolute Integer Y Position of the object
Z int 592 The Absolute Integer Z Position of the object
Yaw byte 0 The yaw in steps of 2p/256
Pitch byte 67 The pitch in steps of 2p/256
Object Data Object Data
Total Size: 22 or 28 bytes

Map Chunk Bulk (0x38)

Server to Client

Packet ID Field Name Field Type Example Notes
0x38 Chunk Count short The number of chunks in this packet
Chunk data length int the size of the data field
Unknown use boolean Has only been observed as true when sniffing a vanilla connection.
Data byte array Compressed chunk data
meta information chunk bulk meta information Chunk count times the Meta information structure (See notes for details)
Total Size: 7 + (Chunk data size) + 12 * (Chunk Count) bytes

Removed Packets

0x15 "Spawn Dropped Item" has been removed, and its purpose is now handled by 0x17 "Spawn Object/Vehicle". The entity type ID is 0x02. You can set the item type by sending an 0x28 "Entity Metadata" packet with a slot at index 10. Vanilla packet dump

Protocol History

1.4.6 Pre-release

Protocol version is now 51. Spawn dropped item (0x15) removed, merged into spawn object (0x17). Map chunk bulk (0x38) adds a boolean field with unknown purpose.


Protocol version is now 50. Packet 0x10 is sent both ways. Packet 0x17 has two new bytes, currently unknown.