Classic Protocol Extension/Old Extensions

The extensions on this page have been deprecated or replaced.

Version 1 (Deprecated since 28 August 2014)

 * Client Behavior
 * When ExtAddPlayerName packet is received for an unrecognized NameID, a new entry must be added to the autocompletion list and tab-list. When receiving ExtAddPlayerName packet for an already-listed NameID, client must update its ListName, GroupName, and GroupRank. Name list must persist when client changes worlds/maps.


 * Names on the tab-list should be grouped by GroupName in the player tab-list. Names within a GroupName should be sorted by GroupRank (in ascending order). Names with the same GroupName and GroupRank should be sorted alphabetically by ListName.


 * When an ExtAddEntity packet is received, it must be treated as the SpawnPlayer packet. InGameName should be shown above the player's heads in-game. Skin should be loaded using the given SkinName for a player name. When client receives ExtAddEntity packet for an already-spawned player, a duplicate entity must not be spawned and existing entity's position should not be changed. Instead their InGameName and SkinName should be updated. If a negative ID is given for ExtAddEntity, client must update player's own spawn point, InGameName, and SkinName. The client must ignore regular SpawnPlayer packets, if any are received. Name list should not be affected by ExtAddEntity.


 * Color codes may be either drawn or stripped from ListName, GroupName, and InGameName.


 * When a standard DespawnPlayer packet is received for a recognized EntityID, player model should be removed from a world. Name list should not be affected by DespawnPlayer.


 * When ExtRemovePlayerName packet is received for a recognized NameID, they should be removed from autocompletion list and tab-list. When DespawnPlayer or ExtRemovePlayerName packet is received for a negative or unrecognized PlayerID, no action should be taken.


 * Server Behavior
 * When a new player connects to the server, ExtAddPlayerName must be sent. GroupName and GroupRank can be used in any way, for example to group players by map/world or rank/class/faction. Server must use ExtAddEntity in place of standard SpawnPlayer packet. Server should re-send ExtAddPlayerName packet, using the identical PlayerID, when player's ListName, GroupName, or GroupRank change. Server must reliably send an ExtRemovePlayerName when the player disconnects. Color codes are permitted in ListName, GroupName, and InGameName.


 * ExtAddPlayerName Packet
 * Server to Client
 * {| class="wikitable"

! class="col0" | Packet ID ! class="col1" | Field Name ! class="col2" | Field Type ! class="col3" | Example ! class="col4" | Notes (22) May be left empty (exclude from autocompletion). A lower number means higher rank. ! class="col0" | Total Size:
 * - class="row0"
 * - class="row1"
 * class="col0 centeralign" rowspan="5" | 0x16
 * class="col1 centeralign" | NameID
 * class="col2 centeralign" | short
 * class="col3 centeralign" |
 * class="col4" | Between 0 and 255
 * - class="row2"
 * class="col1 centeralign" | PlayerName
 * class="col2 centeralign" | string
 * class="col3 centeralign" |
 * class="col4" | Player name used for autocompletion.
 * - class="row3"
 * class="col1 centeralign" | ListName
 * class="col2 centeralign" | string
 * class="col3 centeralign" |
 * class="col4" |Name displayed in the in-game list.
 * - class="row4"
 * class="col1 centeralign" | GroupName
 * class="col2 centeralign" | string
 * class="col3 centeralign" |
 * class="col4" |
 * - class="row5"
 * class="col1 centeralign" | GroupRank
 * class="col2 centeralign" | byte
 * class="col3 centeralign" |
 * class="col4" | Rank of a player within the group.
 * - class="row6"
 * class="col1 rightalign" colspan="4" | 196 bytes
 * }


 * ExtAddEntity Packet
 * Server to Client
 * {| class="wikitable"

! class="col0" | Packet ID ! class="col1" | Field Name ! class="col2" | Field Type ! class="col3" | Example ! class="col4" | Notes (23) ! class="col0" | Total Size:
 * - class="row0"
 * - class="row1"
 * class="col0 centeralign" rowspan="3" | 0x17
 * class="col1 centeralign" | EntityID
 * class="col2 centeralign" | byte
 * class="col3 centeralign" |
 * class="col4" | Between 0 and 127
 * - class="row2"
 * class="col1 centeralign" | InGameName
 * class="col2 centeralign" | string
 * class="col3 centeralign" |
 * class="col4" | Player name to be shown in-game, hovering above player model.
 * - class="row3"
 * class="col1 centeralign" | SkinName
 * class="col2 centeralign" | string
 * class="col3 centeralign" |
 * class="col4" | Player name whose skin should be used by the client.
 * - class="row4"
 * class="col1 rightalign" colspan="4" | 130 bytes


 * }


 * ExtRemovePlayerName Packet
 * Server to Client
 * {| class="wikitable"

! class="col0" | Packet ID ! class="col1" | Field Name ! class="col2" | Field Type ! class="col3" | Example ! class="col4" | Notes (24) Matches NameID of the ExtAddPlayerName packet ! class="col0" | Total Size:
 * - class="row0"
 * - class="row1"
 * class="col0 centeralign" | 0x18
 * class="col1 centeralign" | NameID
 * class="col2 centeralign" | short
 * class="col3 centeralign" |
 * class="col4" | Between 0 and 255
 * - class="row2"
 * class="col1 rightalign" colspan="4" | 3 bytes
 * }

Version 1 (Deprecated since 9 May 2016)

 * This extension allows servers to define new block types with custom IDs and appearance, as well as the ability to redefine the properties of standard block types.
 * Motivation: To allow defining custom block types that do not have minX/Y/Z values of 0, and maxX/Z values of 1.
 * Client Behavior: See the BlockDefinitions specification. Additionally, this extension depends on EnvMapAppearance extension and BlockDefinitions, and must only be enabled if BOTH extensions are mutually supported.


 * Texturing: See the BlockDefinitions specification. The MinX/Y/Z and MaxX/Y/Z fields also affect the location within the terrain tile for a given face that the block should sample texels from. (e.g. if minX and minZ was 8, and maxX and maxZ was 16, then for the terrain.png tile with pixels from (0, 0) to (16, 16), the top face would be drawn with the subset of pixels from (8, 8) to (16, 16))


 * Server Behavior: See the BlockDefinitions specification.

This packet is the same as DefineBlock packet, except the 'shape field' is replaced by 6 fields indicating the bounding box of the block in pixel coordinates. Note that this packet does not support sprites, you must send a regular DefineBlock packet for that.
 * DefineBlockExt Packet
 * Server to Client
 * {| class="wikitable"

! Field Name ! Field Type ! Example ! Notes ! Total Size:
 * Packet ID
 * Packet ID
 * class="centeralign" rowspan="16" | 37
 * class="leftalign" colspan="4" | Following fields from DefineBlock packet: BlockID, Name, Solidity, MovementSpeed, TopTextureID, SideTextureID, BottomTextureID, TransmitsLight, WalkSound, FullBright
 * class="centeralign" | MinX
 * class="centeralign" | byte
 * class="centeralign" |
 * Minimum X coordinate in pixels. Min allowed is 0, max allowed is 15.
 * class="centeralign" | MinY
 * class="centeralign" | byte
 * class="centeralign" |
 * Minimum Y coordinate in pixels. Min allowed is 0, max allowed is 15.
 * class="centeralign" | MinZ
 * class="centeralign" | byte
 * class="centeralign" |
 * Minimum Z coordinate in pixels. Min allowed is 0, max allowed is 15.
 * class="centeralign" | MaxX
 * class="centeralign" | byte
 * class="centeralign" |
 * Maximum X coordinate in pixels. Min allowed is 1, max allowed is 16.
 * class="centeralign" | MaxY
 * class="centeralign" | byte
 * class="centeralign" |
 * Maximum Y coordinate in pixels. Min allowed is 1, max allowed is 16.
 * class="centeralign" | MaxZ
 * class="centeralign" | byte
 * class="centeralign" |
 * Maximum Z coordinate in pixels. Min allowed is 1, max allowed is 16.
 * class="leftalign" colspan="4" | Following fields from DefineBlock packet: BlockDraw, FogDensity, FogR, FogG, FogB
 * Maximum Y coordinate in pixels. Min allowed is 1, max allowed is 16.
 * class="centeralign" | MaxZ
 * class="centeralign" | byte
 * class="centeralign" |
 * Maximum Z coordinate in pixels. Min allowed is 1, max allowed is 16.
 * class="leftalign" colspan="4" | Following fields from DefineBlock packet: BlockDraw, FogDensity, FogR, FogG, FogB
 * class="leftalign" colspan="4" | Following fields from DefineBlock packet: BlockDraw, FogDensity, FogR, FogG, FogB
 * class="leftalign" colspan="4" | Following fields from DefineBlock packet: BlockDraw, FogDensity, FogR, FogG, FogB
 * class="rightalign" colspan="4" | 85 bytes
 * }

Version 1 (Deprecated since 9 May 2016)

 * This extension allows the server to specify custom terrain textures, and tweak appearance of map edges.
 * Motivation: To provide more ways to customize map appearance, including functionality that's currently provided by World of Minecraft's scheme.
 * Client behavior: Client must be able to receive EnvSetMapAppearance packets any time during level load (after the first LevelDataChunk packet is received and until the LevelFinalize packet is received). If the TextureURL field is blank or if the given file could not be loaded for any reason, then the texture pack should be reset to client's default. If an unsupported block ID is given for SideBlock or EdgeBlock, it should be ignored. Given SideLevel value should be adjusted to fit between  and , if necessary. Client should keep using these appearance parameters for future maps, unless specified otherwise by the server.
 * Server behavior: Server may send EnvSetMapAppearance packets after the last LevelDataChunk packet is sent for a level. Server should not use any custom block IDs unless the client declared the appropriate CustomBlocks support level. To reset the texture pack to default value, server should send an EnvMapAppearance packet with empty string for TextureURL. To reset other fields, server should simply use the default values (listed below).
 * Block type restrictions: Only solid blocks are allowed to be used for SideBlock and EdgeBlock. Sprites (Sapling, Dandelion, Rose, BrownMushroom, RedMushroom, Rope, Fire) partial-height blocks (Slab, CobblestoneSlab, Snow), and transparent blocks (Air, Leaves, Glass) cannot be used for those fields.


 * EnvSetMapAppearance packet
 * Server to Client
 * {| class="wikitable"

! class="col0" | Packet ID ! class="col1" | Field Name ! class="col2" | Field Type ! class="col3" | Example ! class="col4" | Notes (30) Must be an HTTP URL, ending with .png, and served with  mime type. Value should be between  and. Default value is. ! class="col0" | Total Size:
 * - class="row0"
 * - class="row1"
 * class="col0 centeralign" rowspan="4" | 0x1E
 * class="col1 centeralign" | TextureURL
 * class="col2 centeralign" | string
 * class="col3 centeralign" |
 * class="col4" | Skin's full URL.
 * - class="row2"
 * class="col1 centeralign" | SideBlock
 * class="col2 centeralign" | byte
 * class="col3 centeralign" |
 * class="col4" | Block ID. Default value is 7 (Admincrete).
 * - class="row3"
 * class="col1 centeralign" | EdgeBlock
 * class="col2 centeralign" | byte
 * class="col3 centeralign" |
 * class="col4" | Block ID. Default value is 8 (Water).
 * - class="row4"
 * class="col1 centeralign" | SideLevel
 * class="col2 centeralign" | short
 * class="col3 centeralign" |
 * class="col4" | Elevation from bottom of the map, in blocks.
 * - class="row5"
 * class="col1 rightalign" colspan="4" | 69 bytes
 * }

Version 2 (Deprecated since 21 June 2017)

 * This extension allows the server to specify custom texture packs, and tweak appearance of map edges.
 * Client behavior: Client must be able to receive EnvSetMapAppearance v2 packets any time during level load (after the first LevelDataChunk packet is received and until the LevelFinalize packet is received). If the TexturePackURL field is blank or if the given file could not be loaded for any reason, then the texture pack should be reset to the client's default. If an unsupported block ID is given for SideBlock or EdgeBlock, it should be ignored. The given SideLevel value should be adjusted to fit between  and , if necessary. Client should keep using these appearance parameters for future maps, unless specified otherwise by the server.
 * Server behavior: Server may send EnvSetMapAppearance v2 packets after the last LevelDataChunk packet is sent for a level. Server should not use any custom block IDs unless the client declared the appropriate CustomBlocks support level. To reset the texture pack to the client's default one, server should send an EnvSetMapAppearance v2 packet with empty string for TexturePackURL. To reset other fields, server should simply use the default values (listed below).
 * Block type restrictions: Only solid blocks are allowed to be used for SideBlock and EdgeBlock. Sprites (Sapling, Dandelion, Rose, BrownMushroom, RedMushroom, Rope, Fire) partial-height blocks (Slab, CobblestoneSlab, Snow), and transparent blocks (Air, Leaves, Glass) cannot be used for those fields.


 * EnvSetMapAppearance v2 packet
 * Server to Client
 * {| class="wikitable"

! class="col0" | Packet ID ! class="col1" | Field Name ! class="col2" | Field Type ! class="col3" | Example ! class="col4" | Notes (30) Must be a HTTP/HTTPS URL, in .zip format, and served with  mime type. If a .png is instead served, this is assumed to represent a terrain.png image. Value should be between  and. Default value is. Value should be between  and. Default value is. Default is 0. (Client has no limit on view distance.) ! class="col0" | Total Size:
 * - class="row0"
 * - class="row1"
 * class="col0 centeralign" rowspan="6" | 0x1E
 * class="col1 centeralign" | TexturePackURL
 * class="col2 centeralign" | string
 * class="col3 centeralign" |
 * class="col4" | Texture pack's full URL.
 * - class="row2"
 * class="col1 centeralign" | SideBlock
 * class="col2 centeralign" | byte
 * class="col3 centeralign" |
 * class="col4" | Block ID. Default value is 7 (Admincrete).
 * - class="row3"
 * class="col1 centeralign" | EdgeBlock
 * class="col2 centeralign" | byte
 * class="col3 centeralign" |
 * class="col4" | Block ID. Default value is 8 (Water).
 * - class="row4"
 * class="col1 centeralign" | SideLevel
 * class="col2 centeralign" | short
 * class="col3 centeralign" |
 * class="col4" | Elevation from bottom of the map, in blocks.
 * - class="row5"
 * class="col1 centeralign" | CloudLevel
 * class="col2 centeralign" | short
 * class="col3 centeralign" |
 * class="col4" | Elevation from bottom of the map, in blocks.
 * - class="row6"
 * class="col1 centeralign" | MaximumViewDistance
 * class="col2 centeralign" | short
 * class="col3 centeralign" |
 * class="col4" | The maximum view distance the client is allowed to see, in blocks.
 * - class="row7"
 * class="col1 rightalign" colspan="4" | 73 bytes
 * }