Minecraft version(s)

1.20.1

Minecraft version details

No response

Mod loader

Forge

Mod loader version

Forge 47.4.2

Fabric API version

No response

In what kind of world or server did the problem occur?

My multiplayer server that I was running

What went wrong? (Crash logs don't go here)

Summary of the issue:

On a Minecraft 1.20.1 server using Forge 47.4.2 (via KettingLauncher, a Forge + Bukkit hybrid loader), the mod Pehkui causes a server crash immediately when a player joins.

Error details
The crash is caused by a Mixin injection failure in:
pehkui.mixins.json:compat1204minus.HorseScreenHandlerMixin
Callback method pehkui$canUse$distance(...) failed injection check
(0/1) succeeded — scanned 1 target(s)

No traditional crash-report file is generated (like crash-report.txt).
Instead, the only message appears in the server logs (latest.log):

[15Jun2025 12:53:20.679] [Server thread/WARN] [/]: ------------------------------------------------------------
[15Jun2025 12:53:20.679] [Server thread/WARN] [/]: A critical error has occurred and your server was shut down.
[15Jun2025 12:53:20.679] [Server thread/WARN] [/]: Error type: Mixin injection error
[15Jun2025 12:53:20.679] [Server thread/WARN] [/]: Caused by: pehkui.mixins.json:compat1204minus.HorseScreenHandlerMixin (Pehkui)
[15Jun2025 12:53:20.680] [Server thread/WARN] [/]: Critical injection failure: Callback method pehkui$canUse$distance(...) failed injection check, (0/1) succeeded

What has been tested:

• ✅ Forge 47.4.0 → Server runs, but Pehkui commands like /scale do not work ("Server version not supported")
• ✅ Forge 47.4.1 → Same as above
• ❌ Forge 47.4.2 → Server crashes as soon as a player joins

Additional info:

• This behavior appeared recently when updating to 47.4.2.
• The server starts normally, but crashes only during player login.
• Hosting uses KettingLauncher, which does not support Forge versions below 47.4.0 — so full downgrade is not possible.

Request:

Is a fix or update planned to make Pehkui compatible with the 47.4.x Forge branch?

Thanks a lot for your work! 🙏

Full list of installed mods and their version numbers

I tested the issue with a minimal setup containing only:

• Pehkui – Pehkui-3.8.2+1.20.1-forge
• SWEM (Star Worm Equestrian Mod) – swem-1.20.1-1.5.3

No other mods were present during the test. The crash still occurs with just these two mods installed.

Did the problem cause the game to crash?

Yes. (paste crash report below)

Full crash report contents (if you experienced a crash)

Crash also happens with SWEM Lite (swemlite-1.20.1-0.1.0.jar), same forge and Pehkui versions as above.

Getting this problem too

This problem is only on forge 1.20.1 version 47.4.2, any below version works fine, so use 47.4.1, I don't think this will be fixed, last update was a year ago