---
title: "Update a Minecraft Server to 26.1+: Java 25, Paper, Plugins"
description: "Update your Minecraft server to 26.1 or newer safely: new version numbers, Java 25, Paper world layout changes, plugin checks and a rollback plan."
url: "https://www.zcraftstudios.com/blog/minecraft-26-1-server-update-guide"
updated: "2026-10-27T04:59:13.441843+00:00"
source: "ZCraft Studios"
---

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# Update a Minecraft Server to 26.1+: Java 25, Paper, Plugins

ZCraft StudiosOct 27, 2026

Update your Minecraft server to 26.1 or newer safely: new version numbers, Java 25, Paper world layout changes, plugin checks and a rollback plan.

## In this guide

- [What changed in 26.1](#what-changed-in-261)
- [Before you start](#before-you-start)
- [Step 1: update Java](#step-1-update-java)
- [Step 2: update your plugins first](#step-2-update-your-plugins-first)
- [Step 3: upgrade Paper and let it migrate the world](#step-3-upgrade-paper-and-let-it-migrate-the-world)
- [Paper config locations](#paper-config-locations)
- [Step 4: test everything](#step-4-test-everything)
- [Things that go wrong](#things-that-go-wrong)
- [Rollback plan](#rollback-plan)
- [Frequently asked questions](#frequently-asked-questions)
- [Related reading](#related-reading)

## Update a Minecraft Server to 26.1+: Java 25, Paper, Plugins

**Quick answer:** Minecraft 26.1 changed three things server owners must plan for: a new year-based version scheme, a **Java 25** requirement, and on Paper a **new world storage layout** that cannot be reversed once your world is upgraded. Back up everything, test on a copy, update plugins first, install Java 25, then upgrade Paper.

_Last checked October 2026 against the PaperMC documentation and release notes. Paper's supported versions change, so confirm on the Paper downloads page before you start._

## What changed in 26.1

| Change | What it means for you |

| --- | --- |

| Year-based versions | Versions now start with the year, then the drop number, then optional patch numbers. After 1.21.11 came 26.1, then 26.1.2, 26.2 and 26.3\. |

| Java 25 | Minecraft 26.1 and newer require Java 25\. Minecraft 1.21.11 and older 1.20 versions use Java 21\. |

| Paper world storage | Dimensions are stored in `world/dimensions/<namespace>/<key>/` instead of separate folders in the server root. |

| Paper build names | Paper versions now look like `26.1.2.build.23-alpha`, using `<mcversion>.build.<build>-<status>`. |

| Plugin compatibility | Plugins need builds that support the new version and Java 25 environment. |

## Before you start

1. **Back up everything.** The Paper release notes warn that you cannot downgrade a world once it has been upgraded to 26.1\. See [Backup Strategy](https://www.zcraftstudios.com/blog/minecraft-server-backup-strategy).
2. **Make a staging copy** and do the whole upgrade there first. See [Staging Environment Guide](https://www.zcraftstudios.com/blog/minecraft-server-staging-environment-guide).
3. **List every plugin** with its current version and check whether each has a build for the new Minecraft version.
4. **Check your host.** Confirm it offers Java 25\. See [Best Minecraft Server Hosting](https://www.zcraftstudios.com/blog/best-minecraft-server-hosting-2026).
5. **Pick the target version.** Check which Paper versions are currently supported and whether the latest builds are still in the alpha channel. If you want stability, choose a version Paper lists as supported with stable builds.

## Step 1: update Java

Install Java 25 and confirm with `java -version`. A hosting panel has a Java or Docker image setting. See [How to Start a Minecraft Server](https://www.zcraftstudios.com/blog/start-minecraft-server) and [RAM and Java Errors](https://www.zcraftstudios.com/blog/minecraft-java-heap-ram-errors).

Review your startup flags. Garbage collector options change between Java versions. See [ZGC for Minecraft Servers](https://www.zcraftstudios.com/blog/zgc-minecraft-server-flags-guide) and [Aikar's Flags Explained](https://www.zcraftstudios.com/blog/aikars-flags-performance-tuning).

## Step 2: update your plugins first

Download the plugin builds that support your target version. On Paper you can stage them:

1. Create a folder named `update` inside `plugins/`.
2. Put the new jars in it, using the same plugin names.
3. Start the server. Paper swaps them in on startup.

Do not remove or edit the jars outside that folder. Examples: EssentialsX 2.22.0 supports 26.1.2, while 2.21.2 was reported to fail on Paper 26.1.2\. See [EssentialsX Config Guide](https://www.zcraftstudios.com/blog/essentialsx-config-guide-messages-chat). If a plugin has no supported build, find a replacement or wait. See [Update Plugins Safely](https://www.zcraftstudios.com/blog/minecraft-server-plugin-update-checklist) and [Plugin Not Loading?](https://www.zcraftstudios.com/blog/minecraft-plugin-not-loading-fix).

## Step 3: upgrade Paper and let it migrate the world

1. Stop the server and confirm the backup.
2. Replace the Paper jar with the new version.
3. Start the server and watch the console. Paper runs a world migration on first start.
4. Do not interrupt the migration.
5. Check the new layout:

```
world/
└── dimensions/
    └── minecraft/
        ├── overworld/
        ├── the_nether/
        └── the_end/
```

Per-world `paper-world.yml` files now live inside each dimension folder. Custom worlds follow the `namespace/key` pattern.

## Paper config locations

Paper keeps its main configuration in a `config/` folder:

- `config/paper-global.yml` for global options
- `config/paper-world-defaults.yml` for defaults that apply to all worlds
- `world/dimensions/<namespace>/<key>/paper-world.yml` for per-dimension overrides

Older guides that point to the server root are describing the previous layout. Paper has said it plans to merge more Bukkit, Spigot and Paper options in a later major release, so check the current docs. See [PaperMC Config Files Explained](https://www.zcraftstudios.com/blog/minecraft-paper-configuration-files-explained).

## Step 4: test everything

| Check | How |

| --- | --- |

| Worlds load | Visit spawn, the Nether and the End |

| Plugins | Read the console for red plugins and errors |

| Permissions and chat | Join with a normal account |

| Economy and data | Check balances, homes and warps |

| Performance | Run [spark](https://www.zcraftstudios.com/blog/how-to-read-spark-profiler-minecraft) with players online |

| Backups | Test a restore |

## Things that go wrong

| Problem | Fix |

| --- | --- |

| Server will not start | Check Java 25 is selected |

| Plugin fails to load | Update to a build for your version, or replace it |

| Missing world or nether | Check the new `world/dimensions/` layout and paths in your plugins |

| Old per-world config ignored | Use the new locations above |

| Multiverse or world plugins show different names | Check dimension keys and the plugin's changelog. See [Multiverse Setup](https://www.zcraftstudios.com/blog/multiverse-multiple-worlds-setup) |

| Pregeneration tool errors | Update it for the new world storage. See [World Pregeneration](https://www.zcraftstudios.com/blog/minecraft-world-pregeneration-launch-guide) |

## Rollback plan

Because the world upgrade is one-way, rollback means restoring the **entire backup** taken before the upgrade, including the old Paper jar, Java version and plugin jars. Keep them together. Test the restore before you start.

## Frequently asked questions

**What Java version does Minecraft 26.1 need?** Java 25.

**Can I downgrade after updating to 26.1?** Not by going backwards. Restore your pre-upgrade backup.

**Why did the Minecraft version numbers change?** Mojang switched to year-based numbering, starting with 26.1.

**Do my plugins still work?** Only if their authors released builds for the new version. Check each one.

**Which Paper version should I choose?** One that Paper lists as supported with stable builds. Check the downloads page.

**Do I need a new host?** Only if your host cannot offer Java 25.

## Related reading

- [Update a Paper Plugin to Minecraft 26.1](https://www.zcraftstudios.com/blog/update-paper-plugin-to-minecraft-26-1)
- [Folia vs Paper vs Purpur](https://www.zcraftstudios.com/blog/minecraft-server-software-paper-purpur-folia)
- [Minecraft Server Staging Environment Guide](https://www.zcraftstudios.com/blog/minecraft-server-staging-environment-guide)

## Continue reading

- [Update a Paper Plugin for Minecraft 26.1: Java 25 Guide](https://www.zcraftstudios.com/blog/update-paper-plugin-to-minecraft-26-1)
- [ZGC for Minecraft Servers: Flags, Java Versions, G1 Choice](https://www.zcraftstudios.com/blog/zgc-minecraft-server-flags-guide)
- [Paper Anti-Xray Settings: Engine Modes and Testing](https://www.zcraftstudios.com/blog/paper-anti-xray-settings-guide)
- [Paper Reload vs Restart: Why Plugins Break After /reload](https://www.zcraftstudios.com/blog/paper-reload-versus-restart-explained)

[ Previous guide Update a Paper Plugin for Minecraft 26.1: Java 25 Guide](https://www.zcraftstudios.com/blog/update-paper-plugin-to-minecraft-26-1)

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