movement anticheat bug

[fikardihno]

General Information

it gets you banned on servers with anticheat

Bug Description

when i join a minecraft server with anticheat while being on viafabric+, it makes you not able to walk around and it gets you banned immediately

Steps to Reproduce

1. launch minecraft 1.21 with viafabricplus
2. change the version in the viafabric plus settings to 1.21.2-1.21.3
3. join a server with an anticheat
4. cannot walk or run around and get banned for no reason

Expected Behavior

you should be able to walk around without getting anticheat detected

[Felix14-v2]

Please, provide the exact steps to reproduce your problem, including your mods list and the server IP.

launch minecraft 1.21 with viafabricplus
change the version in the viafabric plus settings to 1.21.2-1.21.3

Also are you sure you use outdated ViaFabricPlus (1.21) to join newer servers (1.21.2+)?

[DRATHARR]

I have the same problem. I launched the 1.21.4 client and connected to the 1.21.5 server, which has Lightning Grim Anticheat. And I get kicked out immediately when I start walking.
Anticheat says that the problem is in “Simulation” and that's why it kicks me off the server.
I use ViaFabricPlus 4.0.5-BACKPORT (1.21.4)

ViaFabricPlus v4.0.4 Kicks after 10-30 seconds of walking.

On the server, the anti-cheat configuration, Simulation: enabled at threshold: 0.001. If you change it to 0.1, the kicking stops. But the sensitivity of the anti-cheat becomes weaker.

[FlorianMichael]

We only support and provide fixes for the newest ViaFabricPlus versions. Older ViaFabricPlus (and Minecraft) versions are not being supported and may not run stable due to missing updates as well as long-time existing bug fixes.

If you can reproduce any of your issues with the latest ViaFabricPlus version (https://github.com/ViaVersion/ViaFabricPlus/releases/tag/v4.1.4) feel free to open a new issue.