Minecraft Java 26.4 Snapshot 1: Vulkan by Default, Smarter Networking & Cave Fixes
What Changed
Java Edition 26.4 Snapshot 1 dropped on 22 September 2026 and it is a meaty one, touching graphics, networking, world generation, data packs, and a remarkably satisfying stack of bug fixes.
Graphics: Vulkan Is Now the Default
The Graphics API video setting now defaults to "Prefer Vulkan" rather than letting the game pick automatically. If a crash is detected on startup, the game will no longer silently switch APIs on its own, you'll need to change the setting yourself. For most modern devices Vulkan is faster and more stable, so this is a welcome promotion.
Networking Overhaul
This snapshot introduces a significant rework of how clients and servers talk to each other:
- A new mod list packet lets clients tell servers which mods they are running, making debugging much easier. Vanilla clients send an empty list.
- The server address (intention) packet now supports URI-style query parameters, for example,
example.com?key1=value2&key2. This opens the door for servers to pass extra metadata at connection time. - A new
allowed-connection-idsserver property lets dedicated servers whitelist specific connection IDs, blocking anyone who connects without the right ID from even seeing the server status. - A new
status-contact-detailsproperty lets server owners embed contact information directly in the server status response, handy for small private servers with no website. - A new
enable-legacy-statusproperty allows operators to disable the old pre-1.7 ping protocol if they no longer need it.
World Generation & Commands
- Sulfur caves will now generate beneath chunks created before the Caves & Cliffs update when you upgrade an old world.
- The
/fillbiomecommand now fills biomes with block-level accuracy instead of chunk-level accuracy. - Overlapping biome noise entries are no longer permitted, cleaning up some long-standing world-generation edge cases.
- The
straight_trunk_placerfeature gains a new optionaltrunk_widthfield for fatter custom trees.
Blocks & Items
Red and Brown Mushrooms can now be placed on any block with a solid top face regardless of the surrounding light level. They still won't spread unless it's dark enough (brightness below 13) or their support block overrides light requirements.
Bug Fixes
Several long-standing annoyances have finally been resolved, most notably a whole cluster of automatic-jumping bugs in water, players and mobs no longer leap unintentionally when touching walls in water, falling into shallow pools, or being nudged to the edge of liquid. Item frames attached to ceilings also now drop correctly.
Why It Matters
Making Vulkan the default is the most visible change for everyday players, expect smoother frame rates on supported hardware. The networking changes are more quietly significant: the new connection-ID system gives private server operators a lightweight, built-in way to restrict who can even see their server, without relying solely on allowlists. And fixing years-old water-jump bugs makes survival gameplay feel noticeably more polished.
Java and Bedrock
This is a Java Edition-only snapshot. Bedrock Edition is on a separate release track and has received none of these changes. If your household mixes Java and Bedrock players, the Bedrock side is unaffected for now.
For Server Owners
The headline items for server operators are the new dedicated-server properties:
allowed-connection-ids, a comma-separated list of IDs; any client whose address doesn't carry a matching_idparameter is silently refused, which is a neat low-friction privacy tool for invitation-only servers.status-contact-details, embed an email, Discord tag, or any human-readable contact string directly in what clients see in the server list.enable-legacy-status, switch off the antique pre-1.7 ping protocol if you know your players are all on modern clients.
Data Pack authors should note the version bump to 122.0 and the removal of the default_block field from noise settings. Resource Pack authors need to target version 98.0 and update any Order-Independent Transparency shaders that reference the old OIT_WAVELET_RANK or OIT_COEFF_COUNT defines, these have been renamed or removed.
For Parents
Nothing in this snapshot changes how your child plays day-to-day in a significant way. The most noticeable improvement is that the game should run more smoothly on many computers now that Vulkan is the default graphics engine. The long-annoying water-jumping glitch is also gone, which removes a small but real source of frustration during survival play. This is a snapshot, a preview build, so it is not recommended for everyday play just yet.
For Players
Two things you'll notice straight away if you try this snapshot:
- No more phantom jumps in water. You know that infuriating moment when you're swimming against a wall and your character bounces like a rubber ball? Fixed. Multiple related bugs were squashed in one go.
- Mushroom placement freedom. You can now pop a red or brown mushroom on any solid surface, no more hunting for a dark corner just to place the decoration.
Remember, snapshots can be unstable. Always back up your worlds before loading them in a snapshot version, and never use a snapshot build as your main save.
Do SNT Kingdoms Need an Update?
No action needed, and SNT kingdoms cannot run 26.4 clients yet. Our kingdoms run Paper 1.21.11 backends behind a Velocity proxy, with ViaVersion / ViaBackwards / ViaRewind handling clients from version 1.13 all the way up to 1.21.11. Mojang's new year-based versioning (26.x) is not yet supported by PaperMC, Velocity, or the Via family of plugins, so players using the 26.4 snapshot client will not be able to connect to your kingdom at this time.
Our Fabric 1.21.4 backend (home of the SharedLife world) and Geyser + Floodgate for Bedrock crossplay are also unaffected. All six worlds, Survival, SharedLife, RandomLoot, Chaos, Spleef, and Rivals, continue to run normally for all supported client versions. We'll update the compatibility notice on this blog as soon as the broader ecosystem catches up with 26.x.