Fix "Outdated server!" and "Outdated client!" in Minecraft
These two messages tell you the server and the player are on different Minecraft versions, and the message itself tells you which way round. Here is how to read it and what to change.
6 min read · Updated Oct 21, 2026 · By GuavaHost Team
A Java client can only talk to a server running a protocol it understands, so a mismatch is rejected at the door with one of these:
Outdated server! I'm still on 1.21.1
Outdated client! Please use 1.21.4
Both lines are written from the player's point of view, which is where the confusion starts.
| Message the player sees | What it means | The version named is |
|---|---|---|
Outdated server! I'm still on 1.21.1 | The player's client is newer than the server | The player's version |
Outdated client! Please use 1.21.4 | The player's client is older than the server | The server's version |
So "Outdated server! I'm still on 1.21.1" means the player is on 1.21.1 and your server is on something older. "Outdated client! Please use 1.21.4" means your server is on 1.21.4 and the player needs to switch to it.
Read the number, work out whose it is, and you know which side to change.
Option 1: Change the player's version
Usually the easiest fix, and the right one when the server is where you want it.
- Open the Minecraft Launcher and go to Installations.
- Click New installation.
- Pick the exact version the server runs from the version dropdown.
- Give it a name you will recognise, such as "Server 1.21.4", and create it.
- Play that installation instead of Latest release.
Keeping a named installation per server is worth the thirty seconds, because the launcher otherwise updates Latest release out from under you and the error comes back on patch day.
Two details catch people out:
- Snapshots are not releases. A snapshot such as
25w14ais its own protocol and will not connect to a release server, even a very close one. Switch to the matching release. - Modpack launchers pin their own version. If the player uses a third party launcher, the version lives in the pack's profile rather than the vanilla launcher.
Option 2: Change the server's version
Do this when you want everyone on something newer, or when the group has already moved on.
Stop the server first, then open the Version page under Minecraft tools in the server menu and choose the software and version you want. How to change your Minecraft Java server version walks through it screen by screen, including picking between Paper, Vanilla, Forge, Fabric and NeoForge.
Before you click, read the next section. Changing the server version does something to your world that you cannot undo.
The warning: upgrading a world is one way
Minecraft converts your world's data format when a newer version loads it. That conversion is permanent. An older server will refuse to load a world that a newer version has touched, or will load it and corrupt it.
So:
- Take a backup first, every time. Open the Backups page and create one before you change anything. Backups covers how, including keeping a copy away from the server.
- Download that backup. A backup you can only restore from inside the panel is not much use if you want to roll the whole thing back to a different host or an older version.
- Expect seams. New versions often change terrain generation. Chunks you already explored keep their old shape, and new chunks generate with the new rules, which can leave a visible wall or cliff where the two meet.
- Check your plugins and mods. They are version specific. A Paper plugin for 1.20 will usually refuse to load on 1.21, and mods are stricter still.
Upgrade a Minecraft world to a new version safely is the full process, including testing on a copy first. Do not skip the copy if the world matters to you.
Downgrading is the dangerous direction. If you have already started a world on 1.21 and you want 1.20 back, the honest answer is that you restore a pre-upgrade backup or you start a new world. There is no safe in-place downgrade.
Option 3: Let both versions connect with ViaVersion
If your players cannot all agree on a version, there is a third way. ViaVersion is a plugin that translates between Minecraft protocols, so clients on versions other than the server's can still join.
The usual arrangement is to run the newest server you want to support and let older clients in through Via, rather than running an old server. That way your server itself is modern, which means current plugins, current performance work and current bug fixes.
- ViaVersion lets newer clients join an older server.
- ViaBackwards lets older clients join a newer server.
- ViaRewind extends that back to the very old versions.
It is not magic. Features that simply do not exist on an old client cannot be shown to it, so a 1.8 player on a 1.21 server will see substitutes for blocks and items their version never had. For a PvP server where half the players insist on 1.8, that trade is usually worth it. For a server built around new content, it is not.
Let players on different Minecraft versions join with ViaVersion covers where to install it and what breaks.
Bedrock players get a different message
If your players are on Bedrock rather than Java, this error is not the one you want. Bedrock clients update themselves and then refuse to join a server on the older version, with a message about the server using a different version. The fix is to update the server, and Update your Bedrock server version covers it.
A quick routine for version day
When a new Minecraft version lands and your group wants it:
- Take a backup and download it.
- Check that every plugin or mod you depend on has a build for the new version. The one that has not updated is the one that decides your timeline.
- Change the server version from the Version page.
- Start the server and read the Console tab for anything that failed to load.
- Tell your players the new version number so they can make a matching installation.
Doing it in that order turns version day into ten minutes rather than an evening.
Common questions
Which version number is in the Outdated server message?
The player's own. "Outdated server! I'm still on 1.21.1" means the player is running 1.21.1 and your server is older than that. The other message, "Outdated client! Please use 1.21.4", names the server's version instead.
Can I downgrade my server back to an older version?
Not safely with the same world. Loading a world on a newer version converts its data permanently, and an older server will either refuse it or damage it. Restore a backup taken before the upgrade, or start a fresh world on the older version.
Why can my friend on a snapshot not join my release server?
Snapshots use their own protocol, separate from any release, so they never match a release server even when the version numbers look close. Have them switch their launcher installation to the matching release version.
Is ViaVersion a good idea or a last resort?
It is a genuinely useful tool when your players cannot all run the same version, especially on PvP servers. Just expect that content the older client never had will be shown as a substitute, so it suits older-version players joining a modern server better than the other way round.
Still stuck? Jump into our Discord at discord.gg/GuavaHost and the team will help you out.
- minecraft
- java
- version
- mismatch
- troubleshooting
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