How to Change the Minecraft Version of Your Server Safely

To change the Minecraft version of your server without breaking the world, make a backup, stop the server, swap in the new server jar, check that your plugins and mods support the new version, then start it. Going up a version is usually safe. Going down is not, so restore a backup instead.

This guide covers Minecraft Java Edition on Vanilla, Paper, Purpur and Fabric, with a short note on Bedrock. If you are still choosing server software, read Paper vs Purpur vs Fabric first.

Why a version change can break a world

Every Minecraft version saves its world in a slightly different format. When you load an older world in a newer version, the game runs a built-in converter that rewrites each chunk the first time it is loaded. That is why upgrades normally work.

The converter only works in one direction. A newer version can write blocks, biomes, structures or items that an older version does not know about. If you load that world in the older version, the server may refuse to start, or it may load and quietly delete or damage the parts it does not understand. Treat every upgrade as a one-way trip.

Plugins and mods are the second risk. A plugin built for one version can crash on another, and a mod almost never works across versions. Check both before you change anything.

1. Make a backup first

A backup is the only real undo button. Do this before every version change, even a small one.

• Stop the server, or at least let the world save.
• Copy every world folder to a safe place: world by default, plus world_nether and world_the_end on Paper and Purpur. If you are unsure, copy the whole server folder.
• Copy the plugins or mods folder and your config files too.
• Download the backup to your own computer. A backup that lives only on the server is gone if the server is.

If you host with Tree Host, open the Backups tab, give the backup a name like *before the update* and click the button. It saves your worlds and your plugins/ folder, and works while the server is running. The server guide lists the backup options and how restore works.

2. Check that everything supports the new version

Write down what you run now: the server software, the Minecraft version, and every plugin or mod. Then check each item.

• Server software: Paper, Purpur and Fabric usually release a build for a new Minecraft version within days or weeks. Vanilla is ready the day Mojang releases it. Look up the build for the exact version you want before you start.
• Plugins: open each plugin's download page on Modrinth, Hangar or SpigotMC and check its supported versions. Replace any plugin that has not been updated. The guide on how to add plugins to a Minecraft server shows where to find them.
• Mods: on Fabric, every mod needs a build for the new version, and so does Fabric API. If one mod is missing, the server will not start. Wait for the mod or drop it.
• Players: everyone has to join with a matching client, unless you add a compatibility plugin such as ViaVersion.

3. Check your Java version

Each Minecraft release needs a minimum Java version. If it is too old, the server stops at startup with an error about the class file version.

Mojang changed its numbering in 2026, so versions after 1.21 are named by year, such as 26.1. The table still applies: always check the release notes for the version you want, because the Java requirement can change between releases. On Tree Host you can leave the Java setting on Automatic and it picks the right one for the version.

4. Change the version

The steps depend on where you run the server.

• On a host with a dashboard: stop the server, open the settings, find the server software or version option, pick the new version and save. On Tree Host this is Settings, then Server software. The new jar is downloaded on the next start, and your world and plugins are kept.
• On your own machine or a VPS: stop the server, download the new server.jar (or Paper or Purpur jar) for the version, and put it in the server folder. Keep the same file name your start script uses, or update the script. Leave the world folders and server.properties alone.
• On Fabric: download the installer or launcher jar for the new Minecraft version, replace the old one, and replace every mod with the build for that version.

Only the jar changes. Do not delete the world folder, and do not delete server.properties. The new server reads them and upgrades them as needed.

5. Start the server and watch the console

Start the server and keep the console open. A healthy upgrade shows a line like Done, followed by the time it took. The first start is slower than normal, because the server converts data as it loads.

• Look for red errors that name a plugin or mod, and fix those first.
• Join the server and fly around spawn, a build, a farm and the Nether portal. Check that chests, signs and redstone still work.
• Run /version (or version in the console) to confirm the server is on the new version.
• Keep the backup for a few days, until you are sure nothing is wrong.

Tree Host users can also use the quick Version button on the Console tab to check this.

Optional: force-upgrade the whole world

By default, chunks are converted only when a player loads them. That is fine for most servers. If you want everything converted at once, start the server once with the --forceUpgrade option.

• Stop the server and make a backup.
• Start it with java -jar server.jar --forceUpgrade nogui, or add the flag to your start script.
• Wait. A big world can take a long time, and the console shows the progress.
• Start the server normally again.

Most servers do not need this. It helps if you plan to stop using an old version for good, or you want to avoid lag from converting chunks while players explore. Very large worlds can take so long that a hosted server may time out at startup, so try it on a copy first.

What to do if the world broke

Do not try to fix it by hand yet. Go back to the backup.

• Stop the server.
• Put the old server jar back, or select the old version in your settings.
• Restore the backup you made in step 1. This replaces the damaged world with the saved copy. It also throws away anything built since the backup, so make a fresh copy of the broken state first if you might want it.
• Start the server and make sure it works on the old version.
• Find out which plugin or mod caused the problem, then try the upgrade again on a copy.

If the server crashes on startup, the first error in the console is usually the cause. The troubleshooting guide covers the common ones, including the mismatch between your game version and the server version.

Going down a version

Mojang does not support loading a world in an older version than the one that last saved it. If you really need an older version, for example because a modpack requires it, you have two safe choices.

• Restore a backup made before you upgraded, then run the old version on it.
• Start a new world on the old version and rebuild or copy over what you can by hand, such as builds saved as schematics.

Do not just put an older jar on top of a newer world and hope. It might load, and the damage often shows up days later when someone opens a chunk.

Updating a Bedrock server

Bedrock Dedicated Server has its own download. Back up first, stop the server, then replace the program files with the new release. Keep your worlds folder, server.properties, allowlist.json and permissions.json. Bedrock clients usually update automatically, so they will often be ahead of your server and unable to join until you update. The same rule applies: do not go backwards.

A safe upgrade checklist

• Back up the worlds and the plugins or mods, and download a copy.
• Check the new version's Java requirement.
• Check that your server software, plugins and mods have a build for it.
• Change the jar or the version setting, and keep the world folders.
• Start it and read the console for errors.
• Test the server for a day before you delete the backup.

More guides

• How to Make Yourself Op on a Minecraft Server
• How to Whitelist a Minecraft Server (Java and Bedrock)
• How to Move Your Minecraft Server to Tree Host
• Paper vs Purpur vs Fabric vs Folia: Which Minecraft Server Should You Run?