Mystcraft Legacy - Unofficial NeoForge Port

Mystcraft Legacy - Unofficial NeoForge Port

This is an unofficial community port of Mystcraft Legacy 0.13.7.06 to Minecraft 1.21.1 / NeoForge.

This project is not an official Mystcraft release and is not endorsed by Mystcraft Org, XCompWiz, or the original Mystcraft development team.

The goal of this port is to preserve the gameplay and behavior of Mystcraft Legacy as closely as practical while adapting it to the modern Minecraft 1.21.1 / NeoForge engine.

Development Note

Generative AI tools were used during development as assistants for code generation, code review, debugging support, documentation, migration work, and investigation of compatibility issues.

The development process itself was directed by the maintainer. Feature requirements, testing priorities, compatibility goals, implementation requests, design decisions, debugging direction, and proposed fixes were determined by the maintainer based on practical testing and observation.

AI-generated output was not treated as automatically correct. The port was repeatedly compiled, tested in-game, compared against legacy behavior, inspected through logs, and revised based on real test results.

Hands-on debugging and gameplay validation were performed by the maintainer, including bug reproduction, stress testing, verification of fixes, compatibility testing with other mods, and final validation in a large real-world modpack environment.

A public development journal documenting the porting process, practical testing, failed experiments, unexpected bugs, investigation, and revisions is available here:

https://note.com/ueno969_clownrp

Main Features

• Age creation and exploration using Pages, Symbols, and Descriptive Books
• Linking Books, including Intra Linking behavior
• Writing Desk, Book Binder, Ink Mixer, Lectern, Book Receptacle, folders and portfolios
• Crystal Portals with cross-dimension transport support
• Star Fissures
• Legacy Instability systems
• Red, Blue, Purple and White Decay
• Dense Ores
• Compatibility with ores added by other mods
• Runtime Symbols for compatible registered biomes and fluids from loaded mods
• Optional JEI integration
• Compatibility handling for modern world generation and ModernFix without requiring ModernFix

Mod Compatibility

Dense Ores can work with ores supplied by other mods.

Compatible registered modded biomes and fluids can also be exposed as runtime Mystcraft Symbols.

The release candidate was tested inside All the Mods 10 on Minecraft 1.21.1 / NeoForge 21.1.251 / Java 21, including Age creation using Dense Ores and Symbols originating from other mods.

Important Compatibility Notes

This is a modern port, not a block-for-block recreation of the Minecraft 1.12.2 engine.

Legacy behavior and gameplay intent are preserved where practical, but Minecraft 1.21.1 world-generation systems are used underneath.

Known limitations include:

• Occasional structure-start skips at modern WorldGenRegion boundaries as a deliberate crash-prevention measure
• Severe tick load from extreme Instability combinations
• A rare non-fatal vanilla passenger warning during unusually rapid ridden Crystal Portal travel between dimensions
• Incomplete compatibility with third-party add-ons that depend on the old external Mystcraft Instability-provider API

Source Code and Bug Reports

Source code, release history, known issues, and bug reporting are available on GitHub:

https://github.com/ueno96941-Clown/Mystcraft-Legacy-Unofficial-NeoForge-Port

When reporting a bug, please include latest.log, debug.log, Minecraft version, NeoForge version, Mystcraft version, mod list or modpack information, reproduction steps, and the Page/Symbol list used for the Age when relevant.

Upstream and License

Original project:
Mystcraft / Mystcraft Legacy

Original source repository:
https://github.com/Mystcraft/Mystcraft-Legacy

Porting baseline:
Branch: 1.12/develop
Commit: 9bc8ddc061845df0cd5ea47f4fdef773cff786ae
Target legacy version: 0.13.7.06

Mystcraft-derived code and assets are distributed under LGPL-3.0-only in accordance with the upstream license.

Maintainer:
ueno969

NOT AN OFFICIAL MINECRAFT PRODUCT. NOT APPROVED BY OR ASSOCIATED WITH MOJANG OR MICROSOFT.

This product contains trademarks and/or copyrighted works of Cyan. All rights reserved by Cyan. This product is not official and is not endorsed by Cyan.