Compatibility
Minecraft: Java Edition
Platforms
Supported environments
Links
Tags
Creators
Details
This mod is the work of just me (and Github helpers) on a project that I thought could solve one of my biggest complaints, mod compatibility between versions. So I tried to solve it, it is not complete yet so if you can go to Github to improve this mod that would be so helpful to me and the community. If you dont know how to code or just want to donate you can just buy stuff from my server, RevivalSMP's Store https://play.revivalsmp.net/store and get stuff in return. This is getting super long so thank you for reading this and now, onto retromod.
RetroMod
Run old Minecraft mods on new Minecraft. No manual fixes needed.
Drop RetroMod in your mods folder, drop your old mods in the retromod-input folder, and play. RetroMod updates old mods on the fly so they work on current Minecraft.
BETA (v1.0.0-beta.1) — Works well for most mods. Deeper integration mods (shaders, heavy performance mods) may still have rough edges I am fixing. Keep backups of your mod files, just like with any tool that modifies them. Report issues on GitHub.
Fabric is the primary loader. RetroMod runs on Fabric, NeoForge, and Forge, but Fabric is the loader I personally use and where I do most of the testing — so it's where coverage is most complete and where bugs get fixed first. NeoForge support is close behind. Forge support exists but is the least mature; older Forge mods (especially anything compiled with SRG-name obfuscation) often need extra work that's still on the roadmap. If you're picking a loader fresh, pick Fabric for the smoothest experience. Quilt is also supported but by just using its ability to load Fabric mods.
What it does
Have a mod from MC 1.18 you still love? RetroMod rewrites it so it works on MC 26.1. No downloading newer versions, no asking the mod author to update, no giving up on your favorite pack.
- Translates old mods to new Minecraft automatically — from Minecraft 1.12.2 (2017) all the way through 26.1
- Works with Fabric, NeoForge, and Forge — use whatever loader you like
- Handles the hard stuff — method renames, class moves, removed APIs, broken mixins, version-range rejections
- Keeps your originals safe — the mods you drop in are backed up, the transformed copies go in
mods/ - In-game mods menu — click the gear icon on the title screen to see what RetroMod did to each mod
- Fast — uses all your CPU cores briefly during the first launch, then sits out of the way
Mods it knows about
RetroMod has built-in support for 34+ popular mods and modding APIs, so things like JEI, REI, Cloth Config, Trinkets, Curios, GeckoLib, Architectury, Jade, and more get extra-special handling. Using a more obscure mod? The general translation pipeline still applies — most mods translate fine even without specific handling.
Some legacy mods even get automatically shimmed to their modern equivalents:
| Old mod | Works as if you had |
|---|---|
| Baubles | Curios |
| NEI (Not Enough Items) | JEI |
| Thermal Expansion / RF | Forge Energy |
| Old WAILA | Jade |
Supported Minecraft versions
You need MC 1.20 or newer to run RetroMod itself. RetroMod will then translate old mods FROM almost any earlier version:
| Your Minecraft | Old mods it can translate |
|---|---|
| Fabric 1.20 – 26.1 | 1.14 and up |
| NeoForge 1.20.1 – 26.1 | 1.20.1 and up |
| Forge 1.20 – 26.1 | 1.12.2 and up (Java 8 era) |
⚠️ Primary target is Minecraft 26.1+.
RetroMod works on Minecraft 1.20 – 1.21.x and keeps getting better there — the same improvements that go into the 26.1 version (performance, bug fixes, smarter mod handling) show up for you too. But new mods added to the compatibility list and testing effort are focused on Minecraft 26.1+.
If you're on 1.20 or 1.21.x, RetroMod is still a great choice. Upgrading to 26.1 just means you'll see brand-new compatibility coverage land sooner and for more mods.
Why 26.1? It's the first Minecraft version Mojang released without code obfuscation, which is a huge deal for any mod-translation tool. We're pointing our attention at the version of Minecraft going forward from here.
How to use it
Fabric
- Put
retromod-1.0.0-beta.1.jarin yourmods/folder. - Launch Minecraft, then close it. (This creates the
retromod-input/folder.) - Drop your old mods into
retromod-input/. - Launch Minecraft again. RetroMod translates your mods while loading.
- Close Minecraft and launch one more time. Your old mods now work.
The two-launch dance is a Fabric quirk — it checks mod versions before any mod (including RetroMod) gets to run, so we need one launch to translate and one launch to actually load.
Forge / NeoForge
- Put RetroMod in
mods/. - Drop your old mods in
mods/too, or inretromod-input/if you prefer. - Launch. If RetroMod needs to translate anything, it'll prompt you to restart.
- Done.
Works on servers too. Players don't need RetroMod installed to connect to a RetroMod-using server (unless the server is loading client-side mods, which it shouldn't be).
FAQ
What does "beta" mean? Is it safe to install? Yes. "Beta" just means we're still finding edge cases in specific mod combinations. The core pipeline — the part that rewrites your mod files — is well-tested and doesn't touch anything outside the RetroMod folders. Backups are always a good idea with any tool that modifies files, but that's a general habit, not a warning specific to the beta.
Where exactly do I put my old mods?
In the retromod-input/ folder inside your .minecraft/ directory (the one that also contains mods/, saves/, options.txt, etc.). RetroMod creates this folder for you on first launch. If you can't find it, launch Minecraft once with RetroMod installed and it'll appear.
Why does Minecraft have to restart? Fabric in particular checks every mod's declared Minecraft version before any mod gets to run — so RetroMod can't intercept that check on the same launch. We have to translate first, restart, and then Fabric sees the translated versions. Forge and NeoForge work the same way in practice even though the technical reason is different.
Does it work with OptiFine? Not reliably. Most OptiFine features have modern alternatives that work better with RetroMod: Sodium for performance, Iris for shaders, Continuity for connected textures, Zoomify for zoom. We recommend those instead.
Some of my old mod's features stopped working. Why? Sometimes an old mod hooks into Minecraft internals that have been completely rewritten. RetroMod can usually keep the mod loaded even when a specific hook is broken — but that one feature won't do anything. For example, an old item-tooltip mod might load but show nothing new on tooltips. We're adding coverage for these cases in future updates.
My game crashes on startup / when making a new world. Paste your log in a GitHub issue. Most launch crashes are one of a small set of known issues we're fixing. The crash log tells us exactly which mod hit a problem so we can add targeted handling.
Does RetroMod slow down Minecraft?
Only briefly. When you first launch with new mods in retromod-input/, RetroMod spikes your CPU for 1–5 seconds to translate them. After that it does almost nothing — your framerate won't change.
Does it work with Quilt?
Yes — install the Fabric build of RetroMod into your Quilt instance. Quilt Loader runs Fabric mods natively, so the Fabric JAR works on Quilt unchanged. No separate "Quilt build" is needed, and you don't have to translate anything beforehand to put it there. Quilt-native mods you want to translate (the ones that ship with quilt.mod.json instead of fabric.mod.json) are handled too — RetroMod recognizes both formats.
My computer is slow / low on RAM.
Add -Dretromod.parallelism=2 to your Minecraft launcher's JVM arguments. That tells RetroMod to use 2 CPU cores instead of all of them, which uses less memory during translation. Translation will take a bit longer (maybe 10–20 seconds instead of 3) but everything still works.
Something's broken / I found a bug. Please report it on GitHub Issues with your log file. We triage fast — being a beta means we want to hear about problems.
Uninstalling
- Fabric: Remove
retromod-*.jarfrommods/and deleteconfig/fabric_loader_dependencies.json. - Forge / NeoForge: Remove
retromod-*.jarfrommods/. If anything looks off after uninstalling, your original mod files are inmods/retromod-backups/.
Badge for Translated Mods
If you used RetroMod to translate your mod to a newer version, you can optionally add this badge to your mod page description. For CurseForge, just copy the image with the link; for Modrinth and GitHub, use the Markdown or HTML snippet.
Markdown:
[](https://modrinth.com/mod/retromod)
HTML:
<a href="https://modrinth.com/mod/retromod"><img alt="Translated with RetroMod" height="40" src="https://img.shields.io/badge/Translated_with-RetroMod-blue"></a>
Info on AI usage
This project has used AI to help with development, but not so much. 80% of the original code is what I wrote, but I do get AI to make commits on what the code does and also to refine and fix my code if it breaks. I do review every change an AI makes to ensure quality and make sure it isn't breaking stuff while fixing things.
Links
- Source & Issues: github.com/Bownlux/RetroMod
- License: MIT
there's also a standalone CLI tool for transforming mods outside of Minecraft, generating per-mod compatibility reports, and batch-processing whole mod folders. Most people don't need it — the in-game mod handles everything automatically. If you want it anyway, grab it from GitHub Releases (
retromod-X.X.X-cli.jar) and run it withjava -jar retromod-X.X.X-cli.jar help.
Made by Bownlux — part of the team behind RevivalSMP.net