- Loaders
- Fabric
- Downloads on Modrinth
- 119
- Followers on Modrinth
- 1
- versions
- 4
- Updated
- September 12, 2026Sep 12
- Published
- in 2026
At a glance
Needed both in the game and on the server
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.csvitem_mapping.csvbiome_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_pathExample (block_mapping.csv):
immersive_weathering:rooted_grass_block,minecraft:grass_block
croptopia:cinnamon_log,minecraft:jungle_log
byg:yellow_birch_leaves,minecraft:birch_leavesNote: 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