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Legacy Connector documentation

Legacy Connector runs unmodified legacy Forge mods (1.7.10, 1.12.2) on NeoForge 1.21.1 by translating them at load time. This is the technical documentation; the README has installation and the status overview, and the compatibility site lists how each mod works.

Pages

Page What
Architecture Loader, shim, synthesized API, runtime; the legacy loader behaviour that is reproduced
Cache and Redistribution What the translation cache contains, the provenance watermark, why translated jars are not loaded from mods/
Bridges Outdated dependencies replaced by modern mods, and every engine bridge with its state
Library candidates Modern libraries that could replace hand-rolled code (Pehkui adopted for entity size)
World generation Biomes, world types, structures, fluids and input
Mod dimensions Dimensions registered by legacy mods, runtime dimensions, mixed 1.7.10/1.12.2 packs
Entities Entity hosts, AI, attributes, renderers and models
Rendering Textures, block models, tile entity renderers, item renderers
Create and Sable Legacy blocks on Create contraptions and Aeronautics/Sable ships
Recipes Changing legacy recipes with data packs, KubeJS and MineTweaker
Configuration config/legacyconnector.properties
Performance Measured memory, frame rate and startup cost
Troubleshooting Join failures such as "length wider than 21-bit", measuring join payload sizes
Compatibility and status Status per legacy version, known issues, reading the report
Development Building, testing, project layout
Addon API Writing addons for legacy mods
Legacy 1.20.1 estimate Effort, approach options and risks for supporting 1.20.1 Forge (and Sinytra) mods

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