Retromod

Run old Minecraft mods on new Minecraft, automatically. Drop Retromod in mods/, put your old mods in retromod-input/, launch. It rewrites old mod bytecode on the fly so it loads on current Minecraft.

Loaders: Fabric, NeoForge, Forge
Translates mods from: Minecraft 1.12.2 and up
Runs on: Minecraft 1.20 through 26.2
Current stable: 1.1.0 (newest 26.x compatibility, including MC 26.2)
Best on Fabric (most tested); NeoForge close behind; Forge least mature
Compatibility DB and Issues

On MC 26.2, use the OpenGL renderer. 26.2 makes Vulkan the default, which breaks old mods' rendering. Retromod switches you to OpenGL automatically (or set it by hand in Video Settings, Graphics API, OpenGL). On macOS it makes no difference.

What it does

Translates old mods to new Minecraft automatically (MC 1.12.2 through 26.2)
Handles method renames, class moves, removed APIs, broken mixins, and version-range rejections
Backs up your originals; the transformed copies go in mods/
In-game menu (gear icon on the title screen) shows what it did to each mod
Built-in handling for 34+ popular mods and APIs (JEI, REI, Cloth Config, Curios, GeckoLib, Architectury, Jade, Mod Menu, and more)
Some legacy mods are shimmed to their modern equivalents:

Old mod	Works as
Baubles	Curios
NEI	JEI
Thermal Expansion / RF	Forge Energy
Old WAILA	Jade

Not for deep-integration mods (Create, OptiFine, Tinkers, Applied Energistics, and similar). They replace Minecraft's rendering or ship native code, which no automated bytecode tool can bridge. Retromod is for content, quality-of-life, recipe-viewer, and most "normal" mods.

Supported versions

You need MC 1.20 or newer to run Retromod. It then translates old mods from earlier versions:

Your Minecraft	Translates mods from
Fabric 1.20 to 26.2	1.14+
NeoForge 1.20.1 to 26.2	1.20.1+
Forge 1.20 to 26.2	1.12.2+

Primary focus is MC 26.1+ (the first unobfuscated Minecraft); older versions still work and get every core fix.

How to use

Fabric:

Put the Retromod jar for your MC version in mods/.
Launch, then close (this creates retromod-input/).
Drop your old mods into retromod-input/.
Launch again to translate, then restart once so they load.

(The two-launch step is a Fabric quirk: it version-checks mods before any mod, including Retromod, can run.)

Forge / NeoForge:

Put Retromod in mods/.
Drop your old mods in mods/ (or in retromod-input/).
Launch; restart if prompted.

Works on servers, and clients connecting to a Retromod server don't need Retromod themselves. Quilt: use the Fabric build (Quilt runs Fabric mods natively).

FAQ

Is it stable / safe? Yes. 1.1.0 is stable and only touches Retromod's own folders. Keep backups anyway, as with any tool that edits files.
OptiFine? Not reliably. Use Sodium (performance), Iris (shaders), Continuity (connected textures), Zoomify (zoom) instead.
A mod feature stopped working? Retromod keeps the mod loaded even when one hook is broken; that single feature just goes inert. Coverage grows over time.
Crash on startup? Open a GitHub issue with your log. Most launch crashes are known and get targeted fixes.
Slow PC or low RAM? Add -Dretromod.parallelism=2 to your launcher's JVM arguments.
Mod author who wants out? Add an empty META-INF/retromod-opt-out file to your jar; Retromod copies it through untouched.

Full FAQ and details: the README.

Uninstall

Fabric: remove retromod-*.jar from mods/, then delete config/fabric_loader_dependencies.json.
Forge / NeoForge: remove retromod-*.jar from mods/. Your originals are in mods/retromod-backups/.

Translated a mod with Retromod?

Add a badge to your mod page (copy-paste snippets are in the README):

Retromod

What it does

Supported versions

How to use

FAQ

Uninstall

Translated a mod with Retromod?

Links

- License: MIT

Made by Bownlux, part of the team behind RevivalSMP.net.