Guides
Guides
Each guide answers one question and cites the data behind it. Where a number can change, the guide links to the page that keeps it current instead of freezing it in text.
For server owners28
Backing up a Minecraft server before an update
World conversion is one way. Once a world opens on a newer version it will not open on the old one again, which makes the backup the only way back.
3 min read
Can you downgrade a Minecraft world to an older version?
Not with the game. Conversion is one way and there is no built-in path back. What actually happens, what the workarounds cost, and the one thing that always works.
4 min read
Chunky pre-generation breaks mob spawns and empties villages: it's the border, not the plugin
Chunky gets blamed for empty villages and dead terrain after a big pre-generation run. The real cause is a world border or max-world-size setting smaller than the radius you told Chunky to generate.
3 min read
CVE-2026-55010: what Bedrock server admins actually need to do
A critical, unauthenticated remote code execution flaw in Bedrock Dedicated Server, CVSS 9.8. What it actually is, what Microsoft's own patch data says about it, and the one thing that matters regardless of how it's classified.
3 min read
Fixing "Bad packet id" DecoderException in Minecraft
io.netty.handler.codec.DecoderException: java.io.IOException: Bad packet id NN means the server tried to read a packet with the wrong protocol's table. What causes it and the three places to check.
4 min read
Fixing "could not open user_jvm_args.txt" on a Forge server
The file is not optional and the launch script cannot start without it. Why the error is almost never about the file itself, and how to actually fix it.
3 min read
Fixing BungeeCord's IP forwarding error
"If you wish to use IP forwarding, please enable it in your BungeeCord config as well!" comes from three config files that must all agree. Here is each one, and the chat-signing error that looks unrelated but shares a cause.
4 min read
Fixing java.lang.UnsupportedClassVersionError
The exact numbers in this error tell you which side is too old and which class file is too new, before you even open a config file. How to read it, and the fix for each of the two shapes it comes in.
3 min read
Fixing Minecraft server lag: what to measure and in what order
TPS and MSPT measure different things and only one of them tells you what is wrong. How to find the actual cause instead of adding RAM and hoping.
4 min read
Getting your server ready for Minecraft 26.3
26.3 is in pre-release now. What is already known, what to prepare before it ships, and how to be running it on day one without gambling your world on it.
2 min read
How much RAM does a Minecraft server need?
Player count matters less than you think, mods matter more, and giving the server every gigabyte you own makes it slower. What to allocate and why.
3 min read
How to pick a Minecraft host without getting burned
The RAM number on the plan is the least reliable predictor of a good host. What server-owner complaints actually cluster around, and the criteria that matter more than gigabytes.
4 min read
How to verify a Minecraft jar checksum before you run it
A server jar runs with your permissions on your machine. Checking the hash takes ten seconds and is the only way to know the file you got is the file they published.
3 min read
IllegalStateException: Overworld settings missing when moving a world between Paper and vanilla
Paper 26 stores world_gen_settings.dat inside the Overworld dimension folder. Vanilla and NeoForge read it from the shared data folder. Which files to move, in which direction, and why Paper closed the report as working as intended.
3 min read
Installing an .mrpack modpack on a server
An mrpack is a manifest, not a bundle of mods. What is inside it, why the server side is a separate job from the client, and how to get both matching.
3 min read
Java 25 and the 2026 Minecraft releases
The calendar releases raised the Java floor. Which runtime to install, why a newer one is usually fine, and what actually breaks when the requirement moves.
3 min read
Letting Bedrock players join a Java server with Geyser
Geyser translates between the two editions so phone and console players can join a Java server. What it does well, what it cannot do, and how to set it up.
3 min read
Letting many Minecraft versions join one server with ViaVersion
One server, clients from 1.8 to the newest release. How the translation layer works, which plugin covers which direction, and what it genuinely cannot do.
3 min read
Minecraft 26.1 rearranged the world save folder: the full old path to new path map
26.1 moved region, DIM-1, DIM1, playerdata, advancements and stats, and namespaced the data folder. Every old path mapped to its new one, and what quietly breaks if your scripts and tools still use the old ones.
4 min read
Network flush consolidation: the lag bottleneck TPS doesn't show
A healthy TPS doesn't mean a healthy network layer. How per-packet flushing turns into a syscall storm, and how batching those flushes fixes it.
4 min read
NoClassDefFoundError: net/kyori/examination/Examinable on Paper 26.2, and the Adventure 5 break behind it
Paper 26.2, Purpur and Velocity 3.5.0 moved from Adventure 4 to Adventure 5. Plugins compiled against Adventure 4, or bundling a library that was, stop loading. The exact errors, why a server owner cannot fix it, and what a plugin developer changes.
4 min read
Server-side-only mods: what they are and how they work
A mod that runs entirely on the server while every player connects with a plain vanilla client. The client-server split that makes it possible, and exactly what disqualifies a mod from it.
5 min read
Setting up a Velocity proxy network
A proxy moves players between servers without disconnecting them. The setup, the one security setting everyone gets wrong, and when you should not use one at all.
3 min read
The openpty warning on Java 25: harmless, and here is the proof
Java 25 servers on some Linux systems print an UnsatisfiedLinkError about openpty and libutil before the server even starts. What causes it, why it is cosmetic, which JLine version fixes it, and why a newer server jar does not carry that fix yet.
3 min read
Upgrading a Minecraft server from 1.21.11 to 26.1
The jump from the last 1.x release to the first calendar release moves Java, world data and plugin APIs at once. A staged plan that gets you across without losing anything.
4 min read
Upgrading a Minecraft server from 26.1 to 26.2
A drop-to-drop upgrade inside the same year. Much smaller than the jump out of the 1.x line, and there are still four things that will catch you.
3 min read
Which Java version does each Minecraft release need?
Java 25 from 26.1, Java 21 for 1.20.5 to 1.21.11, Java 17 from 1.18, Java 8 below that. The full table for every version in our 903 row spine.
4 min read
Which Minecraft server software should you run in 2026?
Vanilla, Paper, Purpur, Folia, Fabric, NeoForge or a proxy. What each one is actually for, what it costs you, and the one question that decides between them.
4 min read
For players39
"Embeddium instance tainted by mods" is not a crash
Embeddium prints a taint warning naming every mod that patched its internals. It is a support disclaimer, not an error, and removing the named mod usually makes things worse. How to read the line and what it is actually telling you.
4 min read
"Flywheel only supports Sodium 0.6.0-beta.2" when you have neither mod installed
A Forge 1.20.1 crash names two mods that are not in your mods folder. Two separate packaging mechanisms stack to produce it: mods that register under another mod's id, and mods bundled inside other mods. Once you know both, the error reads plainly.
4 min read
Alpha, Beta, Infdev and Classic modding: which project is which
BTW:CE, Back2Beta, BetterBeta, Legacy+ and three separate loaders all target legacy Minecraft, and none of them are the same thing. A map to which one covers your version and where its real wiki lives.
4 min read
Bedrock and Java version numbers: why they never match
Two editions, two numbering schemes, two release cadences. Which number means what, and why a matching number does not mean the same features.
3 min read
Comforts sleeping bags that reset your respawn point to world spawn
The whole point of a Comforts sleeping bag is sleeping without moving your spawn point. Sometimes it does the opposite: your spawn point goes null and you respawn at world spawn instead. What is actually happening and how to protect yourself.
3 min read
Create plus Xaero's Minimap train map crash, explained
Create's bridge to Xaero's Minimap draws train routes there. When Xaero renames an internal class it throws NoClassDefFoundError from Create's compat.
3 min read
CurseForge world downloads: why the map loads with holes, glass or missing textures
The save loads fine but looks broken: black voids, glass blocks, missing skyblock islands. The map is not broken. The zip contained a resource pack that never got installed.
4 min read
Does Oculus need Rubidium or Embeddium? CurseForge's own metadata disagrees
Oculus for 1.20.1 needs Embeddium, but its CurseForge file listings say Rubidium on older builds and say nothing at all on the newest one. The jars and the platform metadata do not match, and no changelog will ever mention it.
4 min read
Duplicate features between content mods: ropes, chairs, and the rest
Why large content mods keep independently adding the same small feature, how to tell it is happening, and the real options for dealing with it.
4 min read
EntityCulling and MoreCulling: modded blocks turn invisible
Culling mods approximate block shapes to decide what not to draw. Modded contraptions and multiblocks break that and vanish. The config keys that fix each mod.
4 min read
Every Minecraft April Fools version
Mojang ships a joke version most years, from 15w14a in 2015 to 26w14a. Release dates, what each one did, and the official downloads.
4 min read
Fabric, NeoForge or Quilt: which mod loader should you use?
Three loaders, three ecosystems, and mods that only work on one of them. What each loader is good at, how fast each updates, and how to pick before you install anything.
3 min read
FerriteCore crashes with Radium or Canary: the one config line that fixes it
FerriteCore and Radium both optimise blockstate allocation, and only one of them can. Set mixin.alloc.blockstate=false in radium.properties or canary.properties. Why the collision exists, and why Radium never shipped the fix.
4 min read
Fixing "Incompatible mod set" and other startup crashes
The loader tells you exactly what is wrong before the game starts. How to read that screen, and the halving method for when it does not name a cause.
3 min read
Fixing "Outdated client" and "Outdated server" in Minecraft
The error names which side is behind, and the protocol number tells you exactly which versions can connect. How to read it, and the three real ways to fix it.
3 min read
Fresh Animations and other CEM packs on Fabric: EMF plus ETF
CEM and emissive textures are OptiFine-only formats. On Fabric or Quilt without OptiFine you need EMF and ETF together, matched, or animations and glow break.
3 min read
GLFW and OpenGL errors in Minecraft: what they mean and how to fix them
GLFW error 65542, GLFW error 65543, OpenGL error 1282 and OpenGL error 1283 all trace back to the graphics driver, not Java. What each code means and the fix that actually works.
4 min read
How to check whether a mod works on your Minecraft version
The three things that must all match, where to find each one, and why "supports 1.21" on a mod page usually does not mean what you think it means.
3 min read
How to Fix 'Incompatible Mods Found!' Error in Minecraft
Step-by-step diagnostic guide to solving the 'Incompatible mods found!' error on Fabric, Quilt, Forge, and NeoForge without reinstalling your entire modpack.
2 min read
How to tell a real mod revival from an unrelated clone
When a popular mod goes dormant, multiple forks appear with names like Reborn, Revival and Continued. Most are not the same project. Here is how to tell which one is.
5 min read
IterationVX & IterationT Shaders for Minecraft: Complete Setup and Settings Guide
How to install and configure IterationVX and IterationT shaders on Minecraft 1.21.11 and 26.x using Iris and Sodium for cinematic lighting, volumetric clouds, and smooth FPS.
1 min read
MCEdit, NBTExplorer, NBT Studio: which world editor is actually alive in 2026
Old lists still point to MCEdit and NBTExplorer. Both are dead. Here is the real chain of successors, including the one that is quietly stalling too.
5 min read
Minecraft 1.21.11 Download, Features and Changes
Everything you need to know about Minecraft 1.21.11 (Mounts of Mayhem): official client and server jar downloads, Java 21 requirement, changes from 1.21, and how it connects to 26.1.
1 min read
Minecraft crashing with exit code -1073740791
This exit code is Windows killing the process over stack corruption, not a Minecraft bug. What the number means and the three things that actually cause it.
3 min read
Minecraft's lost eras and the Legacy+ mods rebuilding them
Classic, Indev, Infdev, Alpha and Beta had mechanics modern Minecraft dropped. Legacy+ isn't preservation; it builds out what each phase could have become.
6 min read
MinecraftOnline and Freedonia: what it takes to run a world since 2010
One Minecraft world, live and unregenerated since the day survival multiplayer shipped in 2010. What keeping that up actually requires, and what is publicly known about the server's 2025 to 2026 dispute with Mojang.
6 min read
OptiFabric plus Fabric API 0.86.0+: why all your text turns into black squares
A specific version pairing breaks font rendering: OptiFabric with OptiFine on Fabric API 0.86.0 or newer turns every glyph in the game into a solid square. What causes it, which versions are safe, and why it was never fixed.
4 min read
OptiFine's decade on top, and why Sodium, Lithium and Iris replaced it
OptiFine was the default Minecraft performance mod for over a decade. Closed source and increasingly awkward on Fabric, it was eventually overtaken by three open, focused alternatives. Here is the actual history.
5 min read
Setting up Sodium and Iris for shaders
OptiFine is no longer the default answer. Sodium plus Iris is faster, actively maintained, and runs most shader packs. What to install and in what order.
3 min read
Storage Drawers: never put a filled drawer through the Framing Table
Running a filled drawer through the Framing Table can silently delete everything inside it. The bug is fixed on Storage Drawers 1.21.4 and newer, but not confirmed fixed on 1.20.1 and older, which is still where most modpacks live.
3 min read
Terralith and TerraBlender: why Superflat, Amplified and Large Biomes get ignored
Pick Superflat, Amplified or Large Biomes with Terralith or any other TerraBlender based biome mod installed and you get a normal world instead, with no error. Why that happens and which world types it hits.
3 min read
The 2011 Minecraft account spoofing exploit, explained
A 2011 flaw let a malicious server hijack a player's Minecraft session using nothing but a blank authentication ID, no password required. What the bug actually was, who found it, and why it has zero bearing on Minecraft's authentication today.
4 min read
What Minecraft snapshot names mean
26w14a, 26.3-snapshot-5, 26.2-pre1, 26.2-rc1. Four naming schemes, what each one tells you, and how far along a release actually is.
3 min read
When a mod's core and addon jars fall out of sync
Xaero's Minimap and XaeroLib, Sophisticated Backpacks and Sophisticated Core: mods shipped as a library jar plus one or more addon jars, and what happens when you update only one of the pair.
4 min read
Why Corpse mod sometimes fails to spawn and you lose items
Corpse's death hook skips on modded vehicles, some modded damage sources and a Ketting fork bug. When it does, no corpse spawns and items drop like vanilla.
4 min read
Why did Minecraft go from 1.21 to 26.1?
Minecraft skipped 1.22 and jumped to 26.1. What the new numbers mean, whether 26.1 is the update 1.22 would have been, and how the old and new versions line up.
3 min read
Why Distant Horizons terrain doesn't get shaded by most shader packs
Distant Horizons renders far terrain through a separate LOD pipeline that shaders don't automatically see. What Iris actually added, which shader packs opted in, and what to check if distant terrain still looks flat or missing.
3 min read
Why performance mods crash when you stack too many of them
ModernFix, Lithium-style mods, and other optimization mods all lean on Mixin to rewrite the game's own code. Stack two that target the same method and they collide, not because either mod is broken.
5 min read
Yet Another Config Lib (YACL v3): Complete Setup and Troubleshooting Guide
Why modern Minecraft mods require Yet Another Config Lib (YACL), how to install YACL v3 on Fabric, NeoForge, and Quilt, and how to fix config screen crashes.
2 min read
For modders8
Armor textures to equipment JSON: why worn armor breaks in 1.21.2+
Armor rendering moved off plain layer_1/layer_2 PNGs and onto a separate equipment JSON system in 1.21.2 through 1.21.4. Updating the item icon does not fix the worn texture. What changed, where the new files live, and how to migrate.
4 min read
CustomModelData to item_model: what changed and when
CustomModelData used to be one integer. It is now a component system split across item_model, a structured custom_model_data list, and per item JSON files. What changed, which version broke it, and how to migrate.
5 min read
Forge version numbers for Minecraft 26.1, 26.2 and 1.21
Forge builds like 65.0.9 carry no hint of the Minecraft version they target. The mapping table for the calendar releases and for the 1.x era.
5 min read
NeoForge version numbers: which build for 26.2 or 1.21
NeoForge moved to four part version numbers in the calendar era. How 26.2.0.35-beta maps to Minecraft 26.2, and how the older 21.1.x rule worked.
4 min read
Porting a mod to a new Minecraft version
Mappings, the compile errors that come first, the behaviour changes that come later, and the order that makes a port take days instead of weeks.
4 min read
Reading Fabric, NeoForge and Quilt version numbers
Every loader numbers itself differently, and NeoForge encodes the Minecraft version in its own. How to read each one, and which numbers must match what.
3 min read
Resource pack format numbers and which Minecraft versions they cover
pack_format is the one field that decides whether your pack loads. What it means, why it keeps changing, and how to support several versions from one file.
3 min read
Why a Fabric mod will never run on NeoForge
Not a licensing choice or a rivalry. A mod is compiled against one loader's API and patched into the game by that loader's machinery. What that means in practice.
3 min read
For developers9
Detecting the Minecraft version from plugin code after calendar versioning
getBukkitVersion() now returns 26.1.2.build.63-stable instead of 1.21.4-R0.1-SNAPSHOT, and code that parsed the old shape or assumed SemVer breaks. What Paper's own people say to use instead, and what to do if you still support Spigot.
4 min read
How to sort Minecraft versions in code after calendar versioning
Semver parsers put 1.21.11 above 26.2 and break. Why Minecraft version strings cannot be compared numerically, and what to sort on instead in code.
5 min read
Minecraft protocol versions: full list and snapshot quirk
Every Java Edition protocol number in one ordered table, what a matching number does and does not guarantee, and why snapshot numbers set the high bit.
5 min read
Paper API Maven and Gradle coordinates
The repository, the artifact, the version string that trips people up, and why paperweight is a different decision from the plain API dependency.
3 min read
plugin.yml api-version values for Minecraft 26.x servers
Bukkit api-version accepted 1.13 through 1.21, then calendar values arrived. What to declare for 26.1 and 26.2, and why a wrong value blocks loading.
5 min read
Protocol versions and data versions, and what each is for
Two numbers that both identify a Minecraft version and answer completely different questions. Which to use for connections, which for save files, and which never to sort by.
3 min read
What breaks plugins when Minecraft gets a new drop
Why a plugin that worked yesterday fails today, which kinds of breakage are recoverable, and how to write one that survives the next drop.
3 min read
Which Minecraft version is newer, 26.2 or 1.21.11?
Text comparison says 1.21.11 wins. Release order says 26.2 does. Why every naive version sort broke in 2026, and how to order both eras correctly in your own code.
4 min read
Writing pack.mcmeta for a data pack
The format number, the folder layout that changed under it, and how to declare a range so one data pack covers several Minecraft versions.
3 min read
For everyone4
Fixing "Connection timed out" and "Connection refused: getsockopt" in Minecraft
getsockopt is the socket call stamped on the error, not the cause. Timed out and refused mean opposite things, and NAT loopback and VPNs produce the identical message for a completely different reason.
6 min read
Fixing "Missing required datapack registries" in Minecraft
The error names the exact registries that don't match, and the namespace in front of each one names the mod. What a datapack registry is, why this is not a version mismatch, and how to fix it.
4 min read
Minecraft version numbering: what happened to 1.22?
Minecraft replaced 1.x numbers with calendar versioning in 2026. How 26.1 and 26.2 work, how snapshots are named now, and how to compare versions across the change.
5 min read
Minecraft's Vulkan renderer: what is changing and why
After 17 years on OpenGL, Java Edition is migrating to a Vulkan-based, multi-threaded renderer. What Vulkan actually changes, what it means for your hardware, and what it means for mods and shaders.
5 min read
server admin1
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