Leaf 1.21.4 Server Jar Download

Newer patch: 1.21.11 Official source

Leaf 1.21.4 build #525 is the latest Leaf build for Minecraft 1.21.4, published on 8 Feb 2026. It requires Java 21 or newer and the jar is 65.4 MB. A newer patch in the same line is available: Leaf 1.21.11.

Download

Download leaf-1.21.4-525.jar65.4 MB

Downloads from github.com — Official — GitHub releases (Winds-Studio/Leaf).

SHA-256 · published by GitHub releases (Winds-Studio/Leaf)
3e2d4036dae06c2aec79864bcd0b36f596488955e7615c0e338cde563fea6657

How to verify this file on Windows, macOS and Linux.

Source: Official — GitHub releases (Winds-Studio/Leaf) SHA-256 shown below Last checked: Report a problem

Version facts

Minecraft release date
This build's date
Build#525
ChannelRelease
Required JavaJava 21 or newer · Temurin 21
File size65.4 MB
Licence / termssee upstream
Upstream projectgithub.com

What changed

Release notes on GitHub What's new in Minecraft 1.21.4 (Minecraft Wiki)

Compatibility

Runs Bukkit, Spigot and Paper plugins built for Minecraft 1.21.4.

Players need a Minecraft: Java Edition 1.21.4 client. Other client versions can join only through a protocol plugin such as ViaVersion/ViaBackwards.

Minecraft 1.21.4 in other server software

Vanilla Paper Spigot CraftBukkit Purpur Folia Leaves Fabric Quilt Forge NeoForge SpongeVanilla

Other Minecraft 1.21.4 server jars (Vanilla, Paper, Fabric, Forge…)

Known issues & safety notes

How to set up Leaf 1.21.4

  1. Install Java 21 or newer (e.g. Eclipse Temurin) and check it with java -version.
  2. Download the Leaf 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.

Linux / macOS — start.sh

#!/bin/sh
# start.sh — Leaf 1.21.4
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 leaf-1.21.4-525.jar nogui

Windows — start.bat

@echo off
REM start.bat — Leaf 1.21.4
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 leaf-1.21.4-525.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=LEAF -e VERSION=1.21.4 --name mc itzg/minecraft-server

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

Upgrading

FAQ

What Java version does Leaf 1.21.4 need?

Leaf 1.21.4 needs Java 21 or newer. Running it on an older Java fails with an UnsupportedClassVersionError mentioning class file version 65.0.

Can 1.21 clients join a 1.21.4 server?

Only if both use the same network protocol, which is not guaranteed between patch releases. Players should use the same version as the server; plugins like ViaVersion (and ViaBackwards for older clients) can bridge versions on plugin servers.