Minecraft 26.2 Pre-Release 1 (Chaos Cubed): what changes for server owners
On 26 May 2026 Mojang shipped the first pre-release of the new Minecraft update labelled 26.2, the drop known as “Chaos Cubed”. It is a test build that previews the full release planned for mid-June. For the average player it mostly means sulfur caves and a new, moody mob. But if you run your own server, this version brings several changes worth knowing about ahead of time. Let’s go through them one by one. No fluff.
What “Chaos Cubed” is, and what Pre-Release 1 is
The whole 26.2 update, “Chaos Cubed”, revolves around a new biome: Sulfur Caves. It is an underground world full of sulfur and cinnabar deposits, new blocks and their variants (stairs, slabs, walls, bricks). The star, though, is the Sulfur Cube: a slime-like mob that can absorb a neighbouring block and take on its properties. Absorb ice? It becomes slippery and slides when hit. That is the “chaos” the drop is named after.
One important distinction here. A pre-release is not the full launch but the final stretch before it. Mojang has closed the feature-adding phase and from now on focuses mostly on fixing bugs. In other words: the mechanics are largely done, and upcoming builds will polish them.
What is new in the game itself
Pre-Release 1 is mostly about refining what earlier snapshots introduced. The key gameplay changes:
- Sulfur Cube refreshed:small sulfur cubes got a new model and texture, their own sounds when fed slimeballs, and each “archetype” of the mob now has unique hit and push sounds.
- Sulfur caves: the biome fog colour was changed and the maximum length sulfur spikes can grow to was reduced; they used to overgrow entire caves.
- Potent Sulfur: a continuous geyser now needs a source lava block to erupt. A small thing, but it changes how farms based on that mechanic are built.
- Chickens:refreshed hurt and death sounds for the “picky” variant. Yes, Mojang cares even about details like this.
- Commands:
/execute on ownernow treats vexes as owned by their evoker. Handy for datapack and adventure-map creators.
The end of the peer-to-peer experiment
The loudest change in this pre-release is the removalof the experimental option to open a singleplayer world to online multiplayer over a peer-to-peer connection. Mojang tested the feature in earlier snapshots but decided that — in their own words — “the experience wasn’t what we wanted it to be for all players” and that it is not ready for release yet.
For dedicated server owners that is actually good news. P2P connections can be unstable and lean on the host’s home line, whereas a server on hosting runs steadily regardless of whether anyone happens to be logged in. Mojang simply confirms that the proven dedicated-server model is still the best path to stable, shared play.
What this means for server owners
This is the part we wrote this post for. Beneath the new mobs sit a few technical changes that directly affect people running a server.
New anti-spam thresholds in server.properties
This is the most interesting addition for admins. The server.properties file gained two new options that help fight chat spam and command flooding, without installing extra plugins:
| Setting | Default value | What it controls |
|---|---|---|
chat-spam-threshold-seconds | 10 | Chat message spam threshold |
command-spam-threshold-seconds | 10 | Command spam threshold |
The mechanism is simple: each message sent adds 1 second to that player’s counter, and the counter drops by 1/20 of a second every game tick. Once the set threshold is exceeded, the player is kicked. You can also set either threshold to 0 to disable it entirely.
Fewer plugins, less overhead
The server now requires Java 25
As the game evolves, so does the minimum required Java runtime: 26.2 needs at least Java SE 25. If you update a server manually on your own machine, be sure to check you have the right version, because on an older one the server simply will not start.
On hosting it is handled for you
New pack formats: check your add-ons
The new version changed the asset formats: the data pack format is now 106.1 and the resource pack format 88.0. In practice that means your own datapacks and textures may need a header update, and engine-specific plugins (e.g. Paper) must be updated to a build compatible with 26.2 before you move a production world onto it.
Performance fixes: very good news
Some players complained about frame drops after the 26.1 update. Pre-Release 1 addresses several of those regressions, which also means smoother play on busy servers:
- Fixed a major framerate drop present from version 26.1 onwards (
MC-307330). - Removed performance drops when rendering decorated pots (
MC-307536) and large numbers of banners (MC-307721), the very things players use to decorate bases en masse. - Improved sulfur cave generation, which used to overgrow with spikes (
MC-307935).
Other notable bug fixes
In total Mojang fixed 32 bugs in this pre-release. Beyond performance, a few are worth noting because they could genuinely break play:
- Players were dying in the bedrock layers when the world spawn fell in the Nether.
- Patched a case where items leaked into the inventory after a player death.
- The friends list loads skins faster and handles long usernames better.
- Added a new (hidden by default) world preset, minecraft:flat_all_dimensions.
Known issue: no Vulkan support
preferredGraphicsBackend to opengl. This is a client-side issue, not a server one, but it is worth warning your community before they start reporting crashes.Should you update your server right now?
Short answer: do not rush the production version. A pre-release is a test build, great for checking out the new features and preparing add-ons, but not for keeping the world your community plays on daily. The stable “Chaos Cubed” release is planned for roughly mid-June 2026, and that is what to wait for before updating your main server.
Rule number one
How to safely test the new version at MineHost
- 1
Back up your world
Before touching anything, make a backup in the panel. It is your safety net if something goes wrong. - 2
Set up a test on a separate server or copy
Do not experiment on production. Run the new version alongside, on a separate world, so you can calmly check add-ons and plugins. - 3
Update the version and Java
In the panel, select a game version compatible with 26.2 and the matching Java runtime. Verify your plugins already have a build for the new version. - 4
Test add-ons and performance
Join the test world, check plugins, datapacks and textures. Only once everything works should you plan the update of your main server.
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