Skip to content

Woalk Datafixer

Configurable DataFixer implementation to replace blocks, items and biomes according to a CSV mapping file

Fabric
Loaders
Fabric
Downloads on Modrinth
119
Followers on Modrinth
1
versions
4
Updated
September 12, 2026Sep 12
Published
in 2026

At a glance

Runs on Fabric
For Minecraft 26.2
Needed in the game and on the server
Latest version — 1.2.1 from September 12, 2026
Requires Easy Data Fix, Fabric Language Kotlin and Fabric API
License GPL-3.0-or-later — free
Where it's needed
In gamerequiredOn serverrequired

Needed both in the game and on the server

Game versions26.2

Woalk Datafixer

Woalk Datafixer is a Fabric mod designed to handle missing or changed blocks, items, and biomes when loading Minecraft worlds. It allows for seamless remapping of registry entries using CSV mapping tables and provides a fallback for items that are completely missing from the registries.

This mod is designed for long-running modded multiplayer servers that, when updating to a new Minecraft version, have to swap out old mods with newer ones, often having other namespaces or item names, and need to preserve world data.

Features

  • DataFixer Mapping: Automatically replaces old block, item, and biome IDs with new ones during world loading using the standard Minecraft DataFixer system.
  • Fallback Item: Any items that are still missing and not covered by the mapping tables are replaced with a special "Unknown" item (wdf:unknown) instead of being lost, helping to preserve inventories and world state.
  • CSV Configuration: Easy to configure using simple CSV files.

Compatibility

  • Minecraft Version: 26.2 (Fabric)
  • Dependencies:

    • Fabric API
    • Easy Data Fix

For multiplayer servers, the mod needs to be installed on both client and server, to ensure that the fallback item is properly registered.

Configuration

The mod reads mapping tables from the config/datafixer/ directory in your Minecraft instance. You can create the following files:

  • block_mapping.csv
  • item_mapping.csv
  • biome_mapping.csv

CSV Format

The CSV files should be simple two-column tables without headers. Each row represents a mapping:

old_namespace:old_path,new_namespace:new_path

Example (block_mapping.csv):

immersive_weathering:rooted_grass_block,minecraft:grass_block
croptopia:cinnamon_log,minecraft:jungle_log
byg:yellow_birch_leaves,minecraft:birch_leaves

Note: The block mapping table is also used to remap the corresponding BlockItems.

License

This project is licensed under GNU GPLv3.

FAQ

How to install Woalk Datafixer?

Install Fabric for your Minecraft version, download Woalk Datafixer for the same version and loader, put the file into the mods folder and launch the game with the loader profile.

Which Minecraft versions does Woalk Datafixer support?

Woalk Datafixer has builds for Minecraft 26.2.

Is Woalk Datafixer needed on the server?

Needed in the game and on the server

License and source
GNU General Public License v3.0 or laterfree to use and share; changes to the mod itself must be published under the same license
Original — Modrinth↗Files unchanged, verified with SHA-512Is this your mod? For rights holders

The site uses cookies: the necessary ones for sign-in and the theme, plus the Yandex Metrica and LiveInternet visit counters — they show us how the site is used. We have no advertising cookies. More