Pre-release protocol

This page documents the changes from the last stable Minecraft release (currently 1.5, protocol 60) to the current pre-release, 13w16a (protocol 62). Note that this page contains bleeding-edge information that may not be completely or correctly documented.

New Packets

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Changed Packets

Update Health (0x08)

Server to Client

http://wiki.vg/Protocol#Update_Health_.280x08.29

Packet ID	Field Name	Field Type	Example	Notes
0x08	Health	float	20.0	0 or less = dead, 20 = full HP
	Food	short	20	0 - 20
	Food Saturation	float	5.0	Seems to vary from 0.0 to 5.0 in integer increments
Total Size:	11 bytes

Entity Action (0x13)

Client to Server

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	Field Name	Field Type	Example	Notes
0x13	EID	int	55534	Player ID
	Action ID	byte	1	The ID of the action, see below.
	Unknown	byte[]	{ 0, 0, 0, 0 }	Probably an int32
Total Size:	10 bytes

Action ID can be one of the following values:

ID	Action
1	Crouch
2	Uncrouch
3	Leave bed
4	Start sprinting
5	Stop sprinting

Player Abilities (0xCA)

Two-Way

The latter 2 bytes are used to indicate the walking and flying speeds respectively, while the first byte is used to determine the value of 4 booleans.

These booleans are whether damage is disabled (god mode, '8' bit), whether the player can fly ('4' bit), whether the player is flying ('2' bit), and whether the player is in creative mode ('1' bit).

To get the values of these booleans, simply AND (&) the byte with 1,2,4 and 8 respectively, to get the 0 or 1 bitwise value. To set them OR (|) them with their repspective masks. The vanilla client sends this packet when the player starts/stops flying with the second parameter changed accordingly. All other parameters are ignored by the vanilla server.

Packet ID	Field Name	Field Type	Example	Notes
0xCA	Flags	byte	5
	Flying speed	byte	12
	Walking speed	byte	25
	Unknown	byte[9]	{ 0xCC, 0xCD, 0x3D, 0xCC, 0xCC, 0xCD, 0x10, 0x00, 0x00 }	Probably multiple fields.
Total Size:	13 bytes

Removed Packets

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Changed Data Types

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Protocol History

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