Supported Minecraft versions and mod loaders
Poly Mod Loader 0.2.0-beta.2 runs Minecraft: Java Edition 26.1, 26.1.1, 26.1.2, 26.2 on Java 25. It runs Poly Mods, Fabric mods, and Forge mods, also together in one game, and Quilt mods as an experiment on 26.2.
Minecraft versions
| Minecraft | How Poly Mod Loader runs it | Forge version it runs for Forge mods |
|---|---|---|
| 26.2 | Its own version modules. The default version in these docs | 65.1.5 |
| 26.1 | Its own version modules | 62.0.9 |
| 26.1.1 | A hotfix that runs on the 26.1 modules | 63.0.2 (no separate test mod set) |
| 26.1.2 | A hotfix that runs on the 26.1 modules | 64.1.5 |
Every version runs on Java 25. The installer offers all four versions, for the launcher profile and for a dedicated server.
Versions that are not in this table are not supported, including all 1.x versions. Since Minecraft 26.1, Mojang ships Java Edition unobfuscated, so mods from every loader use the same names (Mojang's original names) on these versions.
Loaders
| Mods | Status | What it means today |
|---|---|---|
| Poly Mods (Native API) | Verified | Client, server, and world saving are checked |
| Fabric mods | Verified | Entry points, the Fabric Loader API, language adapters, nested jars, Mixin and MixinExtras, class tweakers, and @Environment work as in Fabric Loader. Mods may depend on Poly Mods and other Fabric mods |
| Fabric mods that use Fabric Loader's internal classes | Partial | The parts real mods use are provided (FabricLauncherBase.getLauncher(), FabricLoaderImpl.getGameProvider()). A mod that needs the rest is left out with a reason (POLY-COMPAT-111) |
| Forge mods | Verified | Poly Mod Loader runs Forge and FML themselves. Mods that Forge would refuse are left out first, with the reason (POLY-COMPAT-209) |
| NeoForge mods | Blocked | Left out of the launch by default, with the NeoForge features each one needs in the log. An experiment, off by default, runs NeoForge itself with -Dpoly.neoforge=on: on a 26.2 server, FML loads NeoForge mods, and 20 server-side NeoForge mods from the test set run. A NeoForge mod that NeoForge would refuse is left out with the reason instead of stopping the launch (POLY-COMPAT-217). The client and 26.1 are not checked yet, and NeoForge next to Fabric mods is not supported yet (POLY-COMPAT-216) |
| Quilt mods | Experimental | 26.2 only. quilt.mod.json is read with Quilt Loader's meaning, the Quilt Loader API (org.quiltmc.loader.api) is provided, and Quilt mods' nested jars, entry points, Mixin and access wideners work. Quilt Standard Libraries (QSL) has no release for 26.x, so mods that need it are left out (POLY-COMPAT-114 with 308). A jar with both quilt.mod.json and fabric.mod.json runs as a Fabric mod (310). Not checked yet: 26.1, the client, the dedicated server and install paths, a set of real Quilt mods. Details: Quilt |
Status definitions: Verified / Partial / Experimental / Blocked / Untested. A jar that merely loaded is never labeled Verified. Every jar is either loaded or left out with a reason before game code runs; the reason goes to the log and to .poly/startup-report.json.
Results per version
The test set is the most downloaded mods on Modrinth for each Minecraft version, plus the mods they require. The checks are: load, start, join or create a world, tick, save, and quit. Each mod's features were not checked one by one.
Fabric mods
| Check | 26.2 | 26.1 |
|---|---|---|
| Client: join a saved world, 200 ticks, save and quit to title, stop | 140 mods | 128 mods |
| Real dedicated server start, up to the EULA check | 100 | 93 |
| Game test server: create a world, GameTest, tick, save | 98 | 91 |
The client counts include 2 test mods that drive the run. The only directly installed Fabric mods left out are ones Fabric Loader refuses too.
Forge mods
| Check | 26.2 (Forge 65.1.5) | 26.1 (Forge 62.0.9) | 26.1.2 (Forge 64.1.5) |
|---|---|---|---|
| Client: join a saved world, 200 ticks, save and quit | 40 | 26 | 36 |
| Game test server: create a world, GameTest, save | 32 of 38 | 18 of 36 | 28 of 34 |
| Dedicated server, up to the EULA check | 35 of 41 | 19 of 37 | 31 of 37 |
| Next to Fabric mods | 33 of 39 | 21 of 37 | 30 of 35 |
The Forge mods left out are ones real Forge also leaves out or cannot run: client-only mods on a server, mods built for another Forge, Minecraft, or language loader version (9 on 26.1, all built for 26.1.2), and Mixin configurations that stop Forge's own Mixin. FML stops loading every mod when even one such mod is present; Poly Mod Loader leaves out only that mod.
Running Fabric and Forge mods together, with what still does not work: Run Fabric and Forge mods together. Every diagnostic and error code: Compatibility.