Pre-release protocol
This page documents the changes from the last stable Minecraft release (currently 1.15.2, protocol 578) to the current pre-release (currently 20w12a, protocol 707). 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 | Current | Pre |
| Play clientbound | |||
| Spawn Position | Current | (unchanged) | |
| Display Scoreboard | Current | (unchanged) | |
| Entity Metadata | Current | (unchanged) | |
| Attach Entity | Current | (unchanged) | |
| Entity Velocity | Current | (unchanged) | |
| Entity Equipment | Current | (unchanged) | |
| Set Experience | Current | (unchanged) | |
| Update Health | Current | (unchanged) | |
| Scoreboard Objective | Current | (unchanged) | |
| Set Passengers | Current | (unchanged) | |
| Teams | Current | (unchanged) | |
| Update Score | Current | (unchanged) | |
| Login clientbound | |||
| 0x02 | Login Success | Current | Pre |
New/modified data types
No changes so far.
Entity Metadata
Abstract Arrow
Extends Entity.
Abstract base class for Tipped Arrow (which is used for regular arrows as well as tipped ones) and Spectral Arrow.
| Index | Type | Meaning | Default | |
|---|---|---|---|---|
| 7 | Byte | Bit mask | Meaning | 0 |
| 0x01 | Is critical | |||
| 0x02 | Is noclip (used by loyalty tridents when returning) | |||
| OptUUID | Unused | Empty | ||
| Byte | Peircing level | 0 | ||
Tipped Arrow
Extends Abstract Arrow.
Used for both tipped and regular arrows. If not tipped, then color is set to -1 and no tipped arrow particles are used.
| Index | Type | Meaning | Default | |
|---|---|---|---|---|
| VarInt | Color (-1 for no particles) | -1 | ||
Spectral Arrow
Extends Abstract Arrow.
No additional metadata.
Trident
Extends Abstract Arrow.
| Index | Type | Meaning | Default | |
|---|---|---|---|---|
| VarInt | Loyalty level (enchantment) | 0 | ||
| Boolean | Has enchantment glint | False | ||
Hoglin
Extends Animal.
No additional metadata.
Piglin
Extends Monster.
| Index | Type | Meaning | Default | |
|---|---|---|---|---|
| 15 | Boolean | Is baby | false | |
| 16 | Boolean | Is immune to zombification | false | |
| 17 | Boolean | Is charging crossbow | false | |
Zombie Pigman Zombified Piglin
Extends Zombie.
No additional metadata.
Block Actions
No changes so far.
Inventories
No changes so far.
Plugin Channels
No changes so far.
Play
Clientbound
No changes so far.
Serverbound
No changes so far.
Handshaking
Clientbound
There are no clientbound packets in the Handshaking state, since the protocol immediately switches to a different state after the client sends the first packet.
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, that was used to connect. The Notchian server does not use this information. Note that SRV records are a complete redirect, e.g. if _minecraft._tcp.example.com points to mc.example.org, users connecting to example.com will provide mc.example.org as server address in addition to connecting to it. | |||
| 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
Login Success
| Packet ID | State | Bound To | Field Name | Field Type | Notes |
|---|---|---|---|---|---|
| 0x02 | Login | Client | UUID | Unlike in other packets, this field contains the UUID as The UUID is encoded and decoded as follows, where the int array for decoding is read in the order the bytes are received: public static UUID decodeUuid(int[] is) {
return new UUID((long)is[0] << 32 | (long)is[1] & 4294967295L, (long)is[2] << 32 | (long)is[3] & 4294967295L);
}
public static int[] encodeUuid(long mostSignificantBits, long leastSignificantBits) {
return new int[]{
(int)(mostSignificantBits >> 32),
(int)mostSignificantBits,
(int)(leastSignificantBits >> 32),
(int)leastSignificantBits
};
}
| |
| Username | String (16) |
This packet switches the connection state to play.
Serverbound
No changes so far.
