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How to update a Minecraft server to a new version safely

A new Minecraft version means a new server build, often a new Java and checking every plugin. The world is converted to the new format along the way, and it doesn't go back: since 26.1 Paper says outright that you can't downgrade. So the order is: backup, test on a copy, stable builds — and only then the live server.

The DGuard team5 min read

In short: wait for a stable Paper build for the new version and releases of your key plugins, take a full backup, update Java if the new version needs it, test everything on a copy of the server, and only then update the live one. While the server is still on the old version, ViaVersion lets players with newer clients in.

A new build and a new version are different things

A new build of the same versionA new Minecraft version
ExamplePaper 1.21.11, a newer build1.21.11 → 26.3
The worldUnchangedConverted to the new version's format
Going backPossible: put the old jar backOnly from a backup
PluginsUsually keep workingEach one needs checking
How oftenPaperMC advises at least weeklyWhen the server software and plugins are ready

Builds within a version are fixes and go on regularly — the routine is in Paper. What follows is about moving to a new game version.

What to check before updating

  1. 1A stable server build. Every Paper build has a channel in the downloads API; stable ones are marked STABLE. The first builds of a new version are usually experimental — for a live server, wait for a stable one. Leaf's downloads page says outright which builds aren't recommended for production.
  2. 2Java. Paper 26.1 and newer requires Java 25, while 1.20–1.21.11 ran on Java 21. Moving from 1.21.x to 26.x also means changing Java on the machine or the host.
  3. 3Plugins. Find support for the new version on each plugin's page. The ones that work with packets and server internals matter most: PacketEvents, ViaVersion, the anticheat.
  4. 4A world from Spigot. Since 26.1 a Spigot world can't be moved to Paper directly — it's converted to the Vanilla format first.
  5. 5A backup. A full copy of worlds, plugins and configs — and keep it for a long time: it's your only way back.

The update, step by step

  1. 1

    Back up and make a copy

    Stop the server, save a full archive as in server backups and set up a copy in a separate folder on another port.

  2. 2

    Update the copy

    Install the right Java, replace the server jar with a build of the new version, put in new plugin versions. Start it and read the log.

  3. 3

    Test in game

    Join the copy: claims, economy, permissions, teleports, chests and your mode's mechanics. Test joining from an old client through ViaVersion if you let old versions in.

  4. 4

    Pick a time and warn players

    Announce a maintenance window on Discord and on the server: updating the live server means stopping it.

  5. 5

    Update the live server

    A fresh backup → stop → replace the jar and plugins → start → check the log and /plugins.

  6. 6

    Watch the first days

    Errors in the log, TPS via /mspt and spark, player reports. Keep the pre-update backup until you're sure everything is fine.

While the server is on the old version

Players update their clients faster than stable builds and plugins come out. ViaVersion lets clients newer than the server join, so there's no need to rush. Just keep in mind that ViaVersion itself ships a few days after a game release — more in ViaVersion.

The anticheat during an update

An anticheat is tightly bound to the version: it parses packets and movement physics, so check its support for the new version first. DGuard — the best anticheat for a modern Minecraft server — runs on Paper and Leaf 1.21–26.3. The main version is 1.21.11: DGuard is tested on it and runs on live servers; the other versions are supported but not yet proven on live servers. The current list is on the versions page.

DGuard always needs the latest PacketEvents release next to it — update it along with the server. The DGuard panel shows when a server's PacketEvents is out of date and tells you about it.

FAQ

Can I roll a Minecraft server back to an older version?

Only from a backup taken before the update. PaperMC says plainly that a world upgraded to 26.1 can't go back, and the game warns about world damage when a world is opened in an older version.

Which Java do I need after updating to 26.x?

Java 25: Paper 26.1 and newer requires it, while 1.20–1.21.11 got by with Java 21.

Should I update the server as soon as a new version is out?

No. Wait for a stable server build and releases of your key plugins, and meanwhile let players with new clients in through ViaVersion.

Will plugins update themselves?

No, each plugin has to be updated by hand, and not every one will have a version for the new game. Check the plugin pages before updating the server.

Sources

Read next

All sections
Getting started8 min readMinecraft server backups: what, how and how oftenA server backup means the worlds, the plugins folder with its configs and data, the server's settings files and your plugins' databases. Automate it, keep at least one copy off the machine, and check now and then that you can actually restore from it.ReadPlugins6 min readViaVersion: letting players join from other versionsClients newer than the server: ViaVersion. Older: ViaVersion plus ViaBackwards. Really old 1.7–1.8: add ViaRewind too. If you run an anticheat, install Via on the game server, not the proxy.ReadAdministration5 min readServer crashing or won't start: reading logs and crash reportsThe cause of almost any server crash is written in logs/latest.log or in the crash-reports folder. What's left is finding the first error rather than the last, working out whose code it is — the server's, a plugin's or Java's — and matching it to the typical cases below.Read

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