PaperMC 26.3 Server Guide: Spigot, Plugins, Geyser and Java 25

Short answer (October 13, 2026): PaperMC 26.3 has been stable since October 11, 2026 (first stable build 175; latest build 180 from October 13). Minecraft 26.3 needs Java 25, Spigot 26.3 can be built with BuildTools, and Geyser now lists Java 26.3 as supported (Geyser status checked October 15, 2026). Update Geyser and test crossplay before upgrading a live server. Make a backup first: a world upgraded to 26.3 cannot be downgraded.

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Paper's first 26.3 build appeared on release day, September 15, 2026, and the beta channel opened on September 28. The "Wilderness Bound" drop adds the dappled forest, abandoned camps, cushions and straw beds, and it changes one server default that catches out a lot of new server owners: the whitelist is now on. This guide covers 26.3 from the server side: Java 25, which server software and plugins are ready, upgrading an existing world, and plugin and mod compatibility.

What changed in 26.3 for servers?

For players, 26.3 is an exploration and decoration update. These are the additions you will see on your server:

• Dappled forest: a new autumn forest biome near cold biomes, with red, orange and yellow poplar trees, a full poplar wood set, red shrubs and bouncy shelf mushrooms.
• Abandoned camps: a new structure that appears in many biomes, each in its own style, with chests and barrels. The loot includes maps to other camps and explorer maps to ancient cities, mineshafts, desert pyramids and warm ocean ruins.
• Cushions and straw beds: cushions are for sitting on. A straw bed lets you sleep through one night without changing your spawn point and breaks after use.
• Wool and concrete stairs and slabs, in all sixteen colours.
• Two new commands: /compute and /posteffect.

There are no new mobs in 26.3. For server owners, three technical changes matter more than the new blocks:

• The whitelist is on by default. A freshly generated server.properties now contains white-list=true. A brand-new 26.3 server therefore only lets in players you add with /whitelist add <name>. Set the value to false if you want an open server. An existing server keeps the value that is already in its file. Our whitelist guide explains the commands.
• A new protocol version (777). A 26.2 client cannot join a 26.3 server, and a 26.3 client cannot join a 26.2 server. ViaVersion (5.12.0 or newer) on the server lets 26.3 clients join a 26.2 server; for 26.2 clients on a 26.3 server you also need ViaBackwards. Plan one switchover moment and tell your players in advance.
• New pack formats. Data packs are now format 121.0 and resource packs 97.1. Older packs may show a warning or stop working until their authors update them.

Java 25 requirement

Minecraft 26.3 requires Java 25, just like every version since 26.1 (March 2026). If your server already runs 26.1 or 26.2, nothing changes. If you come from 1.21.11 or older, which ran on Java 21, switch Java first. Otherwise the server stops at startup with an UnsupportedClassVersionError. More background is in which Java version your Minecraft server needs.

On a HostValues game server

The Java version is set by the Docker image in the game panel, under Startup. New HostValues Minecraft servers start on a recent image with Java 25 or newer. If your server was set up for an older Minecraft version and still runs Java 17 or 21, select Java 25 there before you update.

On your own VPS or dedicated server

Install Java 25 yourself. On Debian 13 or a current Ubuntu release:

sudo apt update
sudo apt install openjdk-25-jre-headless

Verify with java -version. The output should start with openjdk version "25. If your distribution does not ship Java 25, use a build from a vendor such as Eclipse Temurin.

Startup flags

Paper recommends the well-known G1 flag set (the "Aikar flags") for 26.x as well, so most startup scripts can stay as they are. Remove any flag that causes an Unrecognized VM option error at startup; options for removed garbage collectors such as -XX:+UseConcMarkSweepGC no longer exist.

Which server software supports 26.3?

Status as of October 7, 2026 (Paper and NeoForge: October 13, 2026). This changes quickly, so check the download pages before you switch.

Practical tip: want the new content right away? Use Vanilla or Fabric. Running Paper with a lot of plugins? Paper 26.3 has been stable since October 11, 2026, so check your key plugins for 26.3 builds first and make a backup before you switch (Java 25). Our comparison of Paper and Purpur helps if you are choosing server software.

Upgrading your world from 26.2 to 26.3

Upgrading a world is straightforward, but a mistake here can cost months of progress. A world that has run on 26.3 cannot be opened cleanly in an older version again, so your backup is your way back.

1. Back up everything. On a HostValues server, create a backup on the Backups tab of the game panel; most plans have two backup slots. On your own machine, copy the whole server directory. See our backup guide.
2. Stop the server cleanly. Type stop in the console and wait until the shutdown has finished.
3. Switch to 26.3. Replace the server jar, or pick 26.3 in the panel. For Fabric, update both Fabric Loader and Fabric API.
4. Start the server and let the first boot finish. Read the console for errors from plugins, mods or data packs.
5. Test. Join, check that your builds are intact and that your important plugins work before you invite everyone back.

New terrain only appears in new chunks

The dappled forest and the abandoned camps only generate in chunks that have never been loaded. Terrain your players already explored stays as it is. You do not need a new world: to reach the new content, players explore further out, or you enlarge the world border.

Generating new chunks costs CPU and disk I/O. When several players explore at the same time on a small plan, you will notice lag spikes. The Chunky plugin, which has a version for 26.3, can pre-generate the area inside your world border while nobody is online. Every pre-generated chunk takes disk space, so check your free space before you start a large radius. More tips are in fixing slow chunk loading.

Custom world generators

If you use a custom generator such as Terra or Iris, that plugin must support 26.3 before you upgrade. An outdated generator can produce broken terrain or crash the server. Check its page on Modrinth or SpigotMC first.

Plugin and mod compatibility

Every new drop breaks some plugins and mods. How you handle that decides whether update day is calm or chaotic.

Before you update

• Make a list of every plugin and mod on your server, with version numbers.
• Check each one on Modrinth, Hangar or SpigotMC for a build that supports 26.3.
• If a critical plugin has no compatible build yet, do not upgrade. Wait for it.

WorldEdit, EssentialsX, LuckPerms and Geyser on 26.3

Status of common plugins as of October 7, 2026:

• WorldEdit: 26.3 is supported in the beta 7.4.6-beta-02 from September 24, for Bukkit, Paper, Spigot and Folia as well as Fabric and NeoForge. The latest stable release, 7.4.5, only goes up to 26.2.
• EssentialsX: no official release for 26.3 yet. The latest release, 2.22.0 from May 31, 2026, supports up to 26.1.2; 26.3 support was added to the development builds on September 15, which you can download from essentialsx.net.
• LuckPerms: works on 26.3. The Bukkit/Paper version is marked compatible with 26.3, and the Fabric and NeoForge versions were updated for 26.3 (current version 5.5.87).
• ViaVersion and ViaBackwards: both support 26.3 since version 5.12.0 from September 18.
• Chunky: marked compatible with 26.3.
• Geyser: the official supported-version list now includes Java 26.3 and Bedrock 26.30 through 26.52 (checked October 15, 2026). The official download service offers Geyser 2.12.0. Update Geyser and check the requirements of your server platform; an older Java backend may need ViaVersion. Our Geyser guide explains the setup.

Plugins that hook deep into the server code are the most likely to break with a new drop, so test those first.

Modpacks

If you run a modpack, do not update individual mods yourself. The pack decides the Minecraft version, and many large packs still run on 1.21.1 or 1.20.1. Wait for the pack author to release a version for 26.3.

How to update on HostValues

On Minecraft server hosting at HostValues you pick Paper 26.3 in the Versions tab and set Java 25 under Startup, Docker Image. Step by step:

1. Log in to the game panel.
2. Create a backup on the Backups tab.
3. Check under Startup that the Docker image is Java 25 or newer.
4. Pick 26.3 and your server software on the Versions tab.
5. Start the server and watch the console during the first boot.

If something goes wrong, restore the backup from the same panel and you are back where you started. Need help with a tricky upgrade? Open a support ticket or ask in our Discord, every day between 10:00 and 22:00 (Dutch time).

Frequently asked questions

When did Minecraft 26.3 come out?

On September 15, 2026. 26.3 "Wilderness Bound" is the third game drop of 2026, after 26.1 in March and 26.2 Chaos Cubed in June. The next one, 26.4, is planned for the fourth quarter of 2026.

Is there a Paper build for 26.3?

Yes. Paper 26.3 has been stable since October 11, 2026 (build 175), after a beta channel that opened on September 28; the latest is build 180 from October 13. For a server with many plugins, check your key plugins for 26.3 builds first and make a backup before you switch (Java 25).

Can I run 26.3 on Java 21?

No. Since 26.1, Minecraft requires Java 25. On an older runtime the server does not start and shows an UnsupportedClassVersionError.

Why can nobody join my new 26.3 server?

Most likely the whitelist. Since 26.3, new servers start with white-list=true. Add players with /whitelist add <name> or set white-list=false in server.properties and restart.

Should I reset my world for 26.3?

Only if you want a fresh start anyway. New biomes and camps appear as soon as players explore new areas, so most servers keep their existing world.

Will my resource pack still work?

The resource pack format changed to 97.1. Older packs may show a warning or display textures incorrectly. Test the pack on a local client first and check whether its author has released an update.

Where do I get the 26.3 server jar?

The vanilla 26.3 server.jar has been on Mojang's download page since September 15, 2026. Paper 26.3 builds (stable since October 11, 2026) are on papermc.io/downloads, and you build Spigot 26.3 yourself with BuildTools. On a HostValues server you pick 26.3 and the server software on the Versions tab instead.

Does my server need to be on 26.3 for Bedrock players to join?

Yes, through Geyser. As checked on October 15, 2026, GeyserMC supports Java 26.3 and Bedrock 26.30 through 26.52. Update Geyser first and verify your server-platform requirements. Geyser connects as a 26.3 client; an older Java server needs a compatible translation setup such as ViaVersion. Back up and test before changing the live server.

Why did my server change after updating to 26.3?

Most changes come from 26.3 itself: data packs and resource packs made for 26.2 may stop working (the formats are now 121.0 and 97.1), plugins without a 26.3 build may not load, and the world is converted on the first start, so it cannot be opened cleanly in 26.2 again. New terrain such as the dappled forest only appears in new chunks, and a freshly generated server.properties turns the whitelist on.

What changed in PaperMC 26.3?

In its 26.3 announcement (September 26, 2026) PaperMC repeats that backups are mandatory, because a world upgraded to 26.3 cannot be downgraded, and plans to merge the Bukkit, Spigot and Paper config files in 26.4. The Paper jar is also about 10 MB smaller, and for plugin developers most of the data component API is no longer experimental, with new events such as those for cushions.

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