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How to upgrade your Minecraft server to 1.21.11



Updated for the Mounts & Mayhem Release. [Read the full changelog.

](https://blog.serverwave.com/minecrafts-mounts-mayhem-update-full-overview-2025-release/)


Minecraft version 1.21.11 introduces new features, bug fixes, and improvements — and updating your Serverwave server takes only a few minutes. This guide explains every method to upgrade, whether you’re using Vanilla, Paper, Purpur, Fabric, Forge, or a custom jar.

This tutorial works for:

  • Minecraft Java Edition 1.21.11
  • Paper 1.21.11
  • Purpur 1.21.11
  • Fabric / Quilt 1.21.11
  • Forge 1.21.11 (when available)
  • Custom jar files


Why Update to Minecraft 1.21.11?

Players search for this update because it includes:

  • Mounts & Mayhem features and fixes
  • Spear combat improvements
  • Performance and stability updates
  • Updated mob behavior
  • Snapshot → Release version corrections

If you want your players to enjoy the latest mechanics, upgrading is essential.


How to Update Your Serverwave Server to Minecraft 1.21.11

Serverwave gives you multiple ways to upgrade your server depending on how you run it. Choose the method that applies to your setup.


What You Need
  • The 1.21.11 server.jar from a trusted source (e.g., Mojang, PaperMC, Purpur, Fabric installer output).


We recommend downloading your jars from https://jarvault.serverwave.com/


Steps

  1. Stop Your Server

Let it fully power down.


  1. Upload the New Jar

SFTP:

  • Connect via SFTP
  • Upload your jar to the root folder


Need help connecting via SFTP? See our guide: How to Use SFTP on Serverwave


  1. Rename the Jar to server.jar

Your server must use this exact filename, or it will not start.


  1. Start Your Server

If the jar is correct, your console will show Minecraft 1.21.11 running.


How to Confirm Your Server Updated Correctly


After starting the server:

  1. Open the console
  2. Look for a line similar to:
Starting minecraft server version 1.21.11
  1. Connect in-game and run:
/version

or for Paper/Purpur:

/version paper
/version purpur


If you see 1.21.11, you're fully updated.


Common Problems & Fixes


❌ *“Unable to access jarfile server.jar”*

Your file is not named server.jar.

Rename it and restart.

❌ *Crashes on startup after updating*

Common causes:

  • Wrong mod versions
  • Plugins incompatible with 1.21.11
  • Fabric/Forge loaders not updated

Check the console for errors or update mods/plugins.

❌ *My Paper/Purpur version doesn't show 1.21.11 yet*

Paper & Purpur sometimes release builds shortly after Mojang’s update.

Try again in a few minutes.

❌ World won’t load after updating

This can happen if you updated from a very old version.

Check the logs for region file errors or try a world backup.


Serverwave Tips for Safe Updating

  • Create a backup before updating — just in case
  • If you use mods, ensure all mods match your new version
  • If your server has heavy plugins, check their 1.21 compatibility
  • For modpacks, always update via the modpack profile, not manually




Updated on: 11/12/2025

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