Outdated Client or Outdated server!: How to Fix Version Mismatch

You try to join a Minecraft server and see “Outdated client!” or “Outdated server!”. This means the Minecraft version you are playing on is not the same as the version the server is running. This guide explains why it happens, how to check the server version, and how to fix it. You can either change your own version, or let other versions join the server with ViaVersion and ViaBackwards.

Why Does This Happen?

Minecraft only lets you join a server that runs the same version as your game. If the versions are different, the server refuses the connection and shows a message.

Message you see	What it means	Simple fix
Outdated client! Please use 1.21.10	Your game is older than the server.	Switch your game to the version in the message.
Outdated server! I'm still on 1.21.10	Your game is newer than the server.	Switch your game to the version in the message.

The version number in the message is the version the server is running. The exact wording can change between Minecraft versions, but the meaning is the same.

In the multiplayer server list, a server on a different version is often shown with a red version number next to it.

Step 1: Check the Server Version with /version

You can find the exact version your server is running with one command.

1. Open the Console in your Pterodactyl panel, or join the server as an operator.

2. Type this command:

   /version

   (In the panel console, you can type version without the slash.)

3. Read the version in the reply. An example (your numbers will be different):

   This server is running Paper version 1.21.10-115-main@a1b2c3d (2026-01-10T12:00:00Z) (Implementing API version 1.21.10-R0.1-SNAPSHOT)

   In this example, the Minecraft version is 1.21.10. That is the version your game must use.

Step 2: Match Your Game to the Server Version

1. Open the Minecraft Launcher.
2. Go to the Installations tab.
3. Click New installation.
4. Under Version, choose the same version as the server, for example release 1.21.10.
5. Give it a name and click Create.
6. Go back to the Play tab, choose your new installation, and click Play.
7. Join the server again.

If you use a different launcher, such as Prism Launcher or MultiMC, create a new instance with the same Minecraft version as the server.

Tip: Make a separate installation for each version. This keeps your worlds and settings from mixing between versions.

Step 3 (Optional): Let Other Versions Join with ViaVersion and ViaBackwards

If you don’t want every player to change their version, you can install plugins that translate between versions. This is useful if some of your players are on a newer or older version than your server.

Plugin	What it does
ViaVersion	Lets players on a newer Minecraft version join your older server.
ViaBackwards	Lets players on an older Minecraft version join your newer server. Needs ViaVersion installed too.
ViaRewind	Lets players on very old versions (such as 1.8) join. Needs ViaVersion and ViaBackwards installed too.

For example, if your server is on 1.21.10:

• Install ViaVersion so a player on a newer version can join.
• Install ViaVersion + ViaBackwards so a player on an older version can join.

How to Install

You can install the plugins in two ways. Option A is the easiest.

Option A: Install from the Panel (One Click)

1. Log in to your panel and open your server.
2. Open the Depot section.
3. At the top, open the Plugins section.
4. In the filter, select your server’s Minecraft version, for example 1.21.10. Use the exact version shown by /version. This makes sure you only see plugins that work with your server.
5. Search for ViaVersion and click Install.
6. If you also need older players to join, search for ViaBackwards and install it too. Do the same for ViaRewind if you need it.
7. Restart your server so the plugins load.

Tip: Always choose your version in the filter before you install. If the version is wrong, the plugin may not work.

Option B: Upload the Files Manually

1. Download the plugin files from a trusted source, such as Hangar (PaperMC’s plugin site), Modrinth, or SpigotMC. Download the latest version of each plugin you need.
2. Stop your server from the Pterodactyl panel.
3. Open the File Manager and go into the plugins folder.
4. Click Upload and upload the .jar files.
5. Start the server.

Check That the Plugins Loaded

After the server starts, type /plugins in the console. An example of the output:

Server Plugins (2):
Bukkit Plugins:
 - ViaBackwards, ViaVersion

If your plugin names are shown in green, they are loaded. If they are red, check the console for an error.

Things to Know About Via Plugins

• Keep the plugins updated. When a new Minecraft version comes out, update ViaVersion and ViaBackwards. Old plugin versions may not support the newest game version.
• Some things may not work perfectly. New blocks, items and features from newer versions may look different or be missing for players on other versions. Some bugs are possible.
• They do not work with every setup. Modded servers (Forge, Fabric) usually require players to have the same mods and version.
• The best experience is when everyone uses the same version. Use Via plugins as a convenience, not a permanent fix for big version differences.

Do Not Downgrade Your Server World

If your server is on a newer version and you want to move it to an older version to match players, do not just change the version. Worlds saved in a newer version can become corrupted or fail to load in an older one. Always make a backup first, and use ViaBackwards to let older players join instead.

Troubleshooting

Problem	What to try
I still get “Outdated client” after changing my version	Make sure you clicked Play on the new installation, and that the version matches what /version shows.
I installed ViaVersion but players still can’t join	Restart the server fully (not /reload). Then update the plugin and check the console for errors.
A newer client cannot join even with ViaVersion	ViaVersion may not support that very new version yet. Update the plugin, or use the server’s version until a new build is released.
An older client cannot join	Install ViaBackwards as well, and update both plugins.
The plugins show red in /plugins	Check that the plugin file is not damaged and supports your server software (Paper) and version.
I use Velocity but installed Via on the backend servers	Move the plugins to the Velocity proxy’s plugins folder.

If you are still stuck, open a support ticket and include the exact message you see, the output of /version, and the Minecraft version your game is using.