entity_teleport serialization errors on 1.21.8

[DereC4]

• [Yes] The FAQ doesn't contain a resolution to my issue

Versions

• mineflayer: 4.33.0
• server: Wolfx 1.21.8
• node: 20.19.19

Detailed description of a problem

When connecting to a server running custom software (Wolfx 1.21.8), Mineflayer throws a stream of errors related to incorrect packet chunk sizes immediately after connecting.

The log is filled with the error: Chunk size is 67 but only 33 was read. Was able to join world still

Your current code

  this.currentBot = mineflayer.createBot({
      host: server.ip,
      port: server.port,
      username: `kmhozcdb@ronaldofmail.com`,
      auth: 'microsoft',
      // version: '1.21.8', // Auto-detect version
      viewDistance: 1,
      hideErrors: false,
  });

Expected behavior

Not sure; is this due to some in-world mods/datapacks not being recognized or parsed correctly?

Additional context

Logs here:

0|cobbleGuard | 2025-10-09T18:32:04: Attempting to connect to 8.138.207.141:25565 Secure chat: false Online Mode: null Version: Wolfx 1.21.8 0|cobbleGuard | 2025-10-09T18:32:08: Chunk size is 67 but only 33 was read ; partial packet : {"name":"entity_teleport","params":{"entityId":1073741824,"x":-194.5,"y":76,"z":61.5,"yaw":0,"pitch":0,"onGround":false}}; buffer :768080808004c0685000000000004053000000000000404ec00000000000000000000000000000000000000000000000000000000000c33125893ff3abb20000000001 0|cobbleGuard | 2025-10-09T18:32:08: Chunk size is 67 but only 33 was read ; partial packet : {"name":"entity_teleport","params":{"entityId":1073741825,"x":-191.5,"y":76,"z":59.5,"yaw":0,"pitch":0,"onGround":false}}; buffer :768180808004c067f000000000004053000000000000404dc0000000000000000000000000000000000000000000000000000000000042ba9d02420c9d230000000001 0|cobbleGuard | 2025-10-09T18:32:08: Chunk size is 67 but only 33 was read ; partial packet : {"name":"entity_teleport","params":{"entityId":1073741829,"x":-194.5,"y":75,"z":68.5,"yaw":0,"pitch":0,"onGround":false}}; buffer :768580808004c0685000000000004052c000000000004051200000000000000000000000000000000000000000000000000000000000c332142f409170cb0000000001 0|cobbleGuard | 2025-10-09T18:32:08: Chunk size is 67 but only 33 was read ; partial packet : {"name":"entity_teleport","params":{"entityId":1073741832,"x":-197.5,"y":76,"z":59.5,"yaw":0,"pitch":0,"onGround":false}}; buffer :768880808004c068b000000000004053000000000000404dc00000000000000000000000000000000000000000000000000000000000c2b89fcb41cc29ab0000000001

[riazkhawaja]

Same issues here trying to work with 1.21.9. I think the protocol used is not up to date for 1.21+.

[extremeheat]

1.21.9 is not supported, latest mineflayer supports is 1.21.8.