Paper 1.21.11 Pre-Release 3 Server Jar Download

Version facts

What changed

Newest upstream commits:

• #6 · 30 Nov 2025 Schedule PlayerSpawnFinder chunk callbacks to mainThreadProcessor instead of server queue fixes #13354 6348ac8
• #4 · 30 Nov 2025 Trigger build after merge commit fdfdec6
• Merge branch 'ver/1.21.10' 2efb4e7
• Restore legacy command restrictions df4b668
• [ci skip] Add missing Nullable annotation for KineticWeapon.Builder methods (#13347) 354a5d5
• #2 · 26 Nov 2025 Update exact choice recipe patch (#13346) 168287b
• #1 · 26 Nov 2025 Update to 1.21.11-pre3 (#13194) a2c9f58
• [ci skip] Mention damage behavior for Server#createWorldBorder (#13338) f8cf03d

Compatibility

Runs Bukkit, Spigot and Paper plugins built for Minecraft 1.21.11 Pre-Release 3.

Players need a Minecraft: Java Edition 1.21.11 Pre-Release 3 client. Other client versions can join only through a protocol plugin such as ViaVersion/ViaBackwards.

Minecraft 1.21.11 Pre-Release 3 in other server software

Known issues & safety notes

• Preview builds are experimental: they can corrupt or irreversibly upgrade worlds, and most plugins and mods do not support them yet. Test on a copy of your world.
• Known issues: search Paper's issue tracker for 1.21.11-pre3

How to set up Paper 1.21.11 Pre-Release 3

1. Install Java 21 or newer (e.g. Eclipse Temurin) and check it with java -version.
2. Download the Paper jar into an empty folder.
3. Start it once with the script below; it creates eula.txt and stops.
4. Set eula=true in eula.txt to accept the Minecraft EULA, then start again. Players join on port 25565.
5. Put plugins (.jar) into plugins/ and restart.

#!/bin/sh
# start.sh — Paper 1.21.11-pre3
cd "$(dirname "$0")"
JAVA_MAJOR=$(java -version 2>&1 | awk -F'"' '/version/ {split($2, v, "."); print (v[1] == "1") ? v[2] : v[1]}')
if [ "$JAVA_MAJOR" -lt 21 ] 2>/dev/null; then
  echo "Java 21 or newer is required (found Java $JAVA_MAJOR)."
  exit 1
fi
java -Xms4G -Xmx4G -XX:+AlwaysPreTouch -XX:+DisableExplicitGC -XX:+ParallelRefProcEnabled -XX:+PerfDisableSharedMem -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1HeapRegionSize=8M -XX:G1HeapWastePercent=5 -XX:G1MaxNewSizePercent=40 -XX:G1MixedGCCountTarget=4 -XX:G1MixedGCLiveThresholdPercent=90 -XX:G1NewSizePercent=30 -XX:G1RSetUpdatingPauseTimePercent=5 -XX:G1ReservePercent=20 -XX:InitiatingHeapOccupancyPercent=15 -XX:MaxGCPauseMillis=200 -XX:MaxTenuringThreshold=1 -XX:SurvivorRatio=32 -jar paper-1.21.11-pre3-6.jar nogui

@echo off
REM start.bat — Paper 1.21.11-pre3
REM Needs Java 21 or newer: run "java -version" to check.
java -Xms4G -Xmx4G -XX:+AlwaysPreTouch -XX:+DisableExplicitGC -XX:+ParallelRefProcEnabled -XX:+PerfDisableSharedMem -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1HeapRegionSize=8M -XX:G1HeapWastePercent=5 -XX:G1MaxNewSizePercent=40 -XX:G1MixedGCCountTarget=4 -XX:G1MixedGCLiveThresholdPercent=90 -XX:G1NewSizePercent=30 -XX:G1RSetUpdatingPauseTimePercent=5 -XX:G1ReservePercent=20 -XX:InitiatingHeapOccupancyPercent=15 -XX:MaxGCPauseMillis=200 -XX:MaxTenuringThreshold=1 -XX:SurvivorRatio=32 -jar paper-1.21.11-pre3-6.jar nogui
pause

The JVM flags are Aikar's G1 flags as recommended by PaperMC. Customise RAM, flags and restart loop →

Rule of thumb: 2–4 GB for a few friends, 6–10 GB for a public server with plugins. Set -Xms equal to -Xmx and leave 1–1.5 GB for the operating system. How much RAM?

Docker

docker run -d -p 25565:25565 -e EULA=TRUE -e TYPE=PAPER -e VERSION=1.21.11-pre3 --name mc itzg/minecraft-server

Uses the community itzg/minecraft-server image, which downloads the file itself.

Upgrading

• Newer: Paper 1.21.11 Pre-Release 4
• Previous: Paper 1.21.10
• How to update a Minecraft server safely