Add support for Minecraft Java Edition 26.1.2

[EMIRKEREM12]

Add support for Minecraft Java Edition 26.1.2

Hello,

Currently, attempting to connect to a 26.1.2 server results in the following error:

Error: unsupported protocol version: 26.1.2.

Setting version: '1.21.4' or version: '1.21.2' in the bot options does not resolve the issue — the server rejects the connection entirely.

Thank you for all the work on this project!

[extremeheat]

Correct, at the moment the latest supported mineflayer version is 1.21.11

[osyra42]

If you are the owner of the server you can use ViaVersion and ViaBackwards, I have had some luck doing this

[Zoooobee]

@osyra42 thanks a lot, It works for me §

[Siigari]

We've submitted a PR to minecraft-data with protocol data for 26.1.2 (protocol 775): PrismarineJS/minecraft-data#1184

The packet ID mappings were extracted from the official server jar using --reports flag. We've verified that a mineflayer bot can connect, complete login, pass through configuration, and enter the play state on a 26.1.2 server using this data.

Additional patches needed in other prismarine packages (prismarine-chunk, prismarine-physics) are version aliases — happy to submit those as separate PRs if the minecraft-data PR is merged.

[walidkorchi]

If you are the owner of the server you can use ViaVersion and ViaBackwards, I have had some luck doing this

The workaround stops at the spawn event, I tried it and indeed the bot joins the server, but when using bot.simpleClick.leftMouse (slot) which is an abstraction of bot.clickWindow(slot, 0, 0), it just does not work after plenty of debugging. The packet size buffers simply do not match with what the servers expects I guess, and I feel like packets sent fail silently specifically from packet_update_time. I tried the 26.1.2 mappings by fetching the protocol from the PR sent to minecraft-data by @Siigari , and as expected, ran into unsupported version error from prismarine-chunk.

Siigari's PR is invalid for the obvious reason of the jar extraction which is against mineflayer's methods of extracting the protocol's mappings, if that makes sense, and instead, use the data generator workflow. In that regard, I'll be linking this #3902 here, which implements the 775 protocol in the modules that mineflayer uses in its internal code and bringing attention for further review from @extremeheat as a needed/active request and a version release in that matter.

26.1 has been around since March 24, 2026 (2 months). It would be great time to support it.

[Corban-Lee]

Any updates on this? It seems that multiple pull requests at the very least attempt to implement 26.1 support, but have yet to be reviewed.