Update Failure with Minecraft - can't update the server to neither 1.21.8 nor 1.21.11

System Information

Field Value
Operating System Linux - Debian GNU/Linux 13 on x86_64
Product AMP ‘Phobos’ v2.6.4.0 (Mainline)
Virtualization Docker
Application Minecraft
Module MinecraftModule
Running in Container Yes
Current State Ready

Problem Description

Issue

I am currently trying to update the minecraft server from me and my friends to 1.21.11
I have tried for days, but sadly had no success. The server either just downgrades itself to 1.21.5 or I can’t join with the right version. As an improvise I tried the same thing with the version 1.21.8, but there is the exact same issue.
In minecraft I always get the notification “Can’t connect to server” if it’s not 1.21.7

please help

Reproduction Steps

  • delete spigot 1.21.8 file
  • change Spigot/CraftBukkit version from 1.21.7 to 1.21.8
  • change Server JAR to 1.21.8
  • update server
  • start server
  • repeatable with other versions