[Bug] neoforge mod need language provider

[maksmanus]

Retromod version

1.0.0-beta.2

Host MC version

26.1.2

Mod loader

NeoForge

Loader version

26.1.2.58-beta

Source mod (name and version)

Not

Source mod's original MC version

Not

What happened

Mod file retromod needs language provider java:26.1 or above to load,

We have found 11.0

null# Minecraft launcher log started at 2026-05-19 08:06:47

Profile: ffff

[08:06:48] [main] [net.neoforged.fml.startup.Entrypoint/INFO]: JVM Uptime at startup: 192ms
[08:06:48] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: Starting FancyModLoader version 11.0.13 (CLIENT in PROD)
[08:06:48] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: Game directory: D:\AstralRinth App\profiles\ffff
[08:06:48] [main] [net.neoforged.fml.loading.EarlyServiceDiscovery/INFO]: Found 2 early service jars (out of 104) in 32ms
[08:06:48] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: Loading FML Early Services:
[08:06:48] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: - D:/AstralRinth App/meta/libraries/net/neoforged/fancymodloader/earlydisplay/11.0.13/earlydisplay-11.0.13.jar
[08:06:48] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: - D:/AstralRinth App/meta/libraries/net/neoforged/fancymodloader/loader/11.0.13/loader-11.0.13.jar
[08:06:48] [main] [net.neoforged.fml.loading.ImmediateWindowHandler/INFO]: Loading ImmediateWindowProvider fmlearlywindow
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.locators.GameLocator/INFO]: Marking unmodified client jar as claimed to prevent loading: D:\AstralRinth App\meta\versions\26.1.2-26.1.2.58-beta\26.1.2-26.1.2.58-beta.jar
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.locators.GameLocator/INFO]: Failed to find common Minecraft classes and resources on the classpath. Assuming we're launching production.
[08:06:48] [fml-loadingscreen] [net.neoforged.fml.earlydisplay.render.LoadingScreenRenderer/INFO]: GL info: Intel(R) UHD Graphics GL version 3.3.0 - Build 30.0.101.2079, Intel
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.ModDiscoverer/INFO]: Found mod file "minecraft-client-patched-26.1.2.58-beta.jar" [locator: game locator, reader: mod manifest]
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.ModDiscoverer/INFO]: Found mod file "neoforge-26.1.2.58-beta-universal.jar" [locator: game locator, reader: mod manifest]
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.ModDiscoverer/INFO]: Found mod file "retromod-1.0.0-beta.2+26.1.2.jar" [locator: {mods folder locator at D:\AstralRinth App\profiles\ffff\mods}, reader: mod manifest]
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.locators.JarInJarDependencyLocator/INFO]: Found 2 dependencies adding them to mods collection
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.ModDiscoverer/INFO]: Found gamelibrary file "mixinextras-neoforge-0.5.4.jar" [parent: neoforge-26.1.2.58-beta-universal.jar, locator: jarinjar, reader: mod manifest]
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.ModDiscoverer/INFO]: Found library file "net.neoforged.neoforge-coremods-26.1.2.58-beta.jar" [parent: neoforge-26.1.2.58-beta-universal.jar, locator: jarinjar, reader: mod manifest]
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.ModDiscoverer/INFO]: Mod List:
Name Version (Mod Id)

	Minecraft 26.1.2 (minecraft)
	NeoForge 26.1.2.58-beta (neoforge)
	Retromod 1.0.0-beta.2 (retromod)

[08:06:49] [main] [mixin/INFO]: SpongePowered MIXIN Subsystem Version=0.8.7 Source=file:/D:/AstralRinth%20App/meta/libraries/net/fabricmc/sponge-mixin/0.17.3+mixin.0.8.7/sponge-mixin-0.17.3+mixin.0.8.7.jar Service=FML Env=CLIENT
[08:06:49] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: Loading FML Plugins:
[08:06:49] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: - ~libraries/net/neoforged/neoforge/26.1.2.58-beta/neoforge-26.1.2.58-beta-universal.jar > net.neoforged.neoforge-coremods-26.1.2.58-beta.jar
[08:06:49] [main] [net.neoforged.fml.loading.LanguageProviderLoader/ERROR]: Language loader javafml version 11.0 is incompatible with [26.1,) required by jar(mods/retromod-1.0.0-beta.2+26.1.2.jar)
[08:06:49] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: Closing FML Loader 51b01960
[08:06:49] [main] [net.neoforged.fml.loading.modscan.BackgroundScanHandler/ERROR]: An error occurred scanning file jar(~libraries/net/neoforged/minecraft-client-patched/26.1.2.58-beta/minecraft-client-patched-26.1.2.58-beta.jar)
java.util.concurrent.CancellationException
at java.base/java.util.concurrent.CompletableFuture.cancel(Unknown Source)
at net.neoforged.fml.loading.moddiscovery.ModFile.close(ModFile.java:246)
at net.neoforged.fml.loading.FMLLoader.close(FMLLoader.java:239)
at net.neoforged.fml.loading.FMLLoader.create(FMLLoader.java:415)
at net.neoforged.fml.startup.Entrypoint.startup(Entrypoint.java:65)
at net.neoforged.fml.startup.Client.main(Client.java:17)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at com.modrinth.theseus.MinecraftLaunch.relaunch(MinecraftLaunch.java:61)
at com.modrinth.theseus.MinecraftLaunch.main(MinecraftLaunch.java:28)
[08:06:49] [main] [net.neoforged.fml.loading.modscan.BackgroundScanHandler/ERROR]: An error occurred scanning file jar(~libraries/net/neoforged/minecraft-client-patched/26.1.2.58-beta/minecraft-client-patched-26.1.2.58-beta.jar)
[08:06:49] [main] [net.neoforged.fml.ModLoader/INFO]: Clearing ModLoader
[08:06:49] [main] [net.neoforged.fml.startup.Entrypoint/ERROR]: Failed to start FML: net.neoforged.fml.ModLoadingException: Loading errors encountered:
- Mod File mods/retromod-1.0.0-beta.2+26.1.2.jar needs language provider javafml:26.1 or above to load
We have found 11.0

at net.neoforged.fml.loading.LanguageProviderLoader.findLanguage(LanguageProviderLoader.java:79)
at net.neoforged.fml.loading.moddiscovery.ModFile.lambda$identifyLanguage$0(ModFile.java:185)
at java.base/java.util.stream.ReferencePipeline$3$1.accept(Unknown Source)
at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(Unknown Source)
at java.base/java.util.stream.AbstractPipeline.copyInto(Unknown Source)
at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(Unknown Source)
at java.base/java.util.stream.AbstractPipeline.evaluate(Unknown Source)
at java.base/java.util.stream.AbstractPipeline.evaluateToArrayNode(Unknown Source)
at java.base/java.util.stream.ReferencePipeline.toArray(Unknown Source)
at java.base/java.util.stream.ReferencePipeline.toArray(Unknown Source)
at java.base/java.util.stream.ReferencePipeline.toList(Unknown Source)
at net.neoforged.fml.loading.moddiscovery.ModFile.identifyLanguage(ModFile.java:186)
at net.neoforged.fml.loading.FMLLoader.create(FMLLoader.java:377)
at net.neoforged.fml.startup.Entrypoint.startup(Entrypoint.java:65)
at net.neoforged.fml.startup.Client.main(Client.java:17)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at com.modrinth.theseus.MinecraftLaunch.relaunch(MinecraftLaunch.java:61)
at com.modrinth.theseus.MinecraftLaunch.main(MinecraftLaunch.java:28)

Crash log or relevant log output

null# Minecraft launcher log started at 2026-05-19 08:06:47
# Profile: ffff 


[08:06:48] [main] [net.neoforged.fml.startup.Entrypoint/INFO]: JVM Uptime at startup: 192ms
[08:06:48] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: Starting FancyModLoader version 11.0.13 (CLIENT in PROD)
[08:06:48] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: Game directory: D:\AstralRinth App\profiles\ffff
[08:06:48] [main] [net.neoforged.fml.loading.EarlyServiceDiscovery/INFO]: Found 2 early service jars (out of 104) in 32ms
[08:06:48] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: Loading FML Early Services:
[08:06:48] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: - D:/AstralRinth App/meta/libraries/net/neoforged/fancymodloader/earlydisplay/11.0.13/earlydisplay-11.0.13.jar
[08:06:48] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: - D:/AstralRinth App/meta/libraries/net/neoforged/fancymodloader/loader/11.0.13/loader-11.0.13.jar
[08:06:48] [main] [net.neoforged.fml.loading.ImmediateWindowHandler/INFO]: Loading ImmediateWindowProvider fmlearlywindow
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.locators.GameLocator/INFO]: Marking unmodified client jar as claimed to prevent loading: D:\AstralRinth App\meta\versions\26.1.2-26.1.2.58-beta\26.1.2-26.1.2.58-beta.jar
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.locators.GameLocator/INFO]: Failed to find common Minecraft classes and resources on the classpath. Assuming we're launching production.
[08:06:48] [fml-loadingscreen] [net.neoforged.fml.earlydisplay.render.LoadingScreenRenderer/INFO]: GL info: Intel(R) UHD Graphics GL version 3.3.0 - Build 30.0.101.2079, Intel
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.ModDiscoverer/INFO]: Found mod file "minecraft-client-patched-26.1.2.58-beta.jar" [locator: game locator, reader: mod manifest]
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.ModDiscoverer/INFO]: Found mod file "neoforge-26.1.2.58-beta-universal.jar" [locator: game locator, reader: mod manifest]
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.ModDiscoverer/INFO]: Found mod file "retromod-1.0.0-beta.2+26.1.2.jar" [locator: {mods folder locator at D:\AstralRinth App\profiles\ffff\mods}, reader: mod manifest]
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.locators.JarInJarDependencyLocator/INFO]: Found 2 dependencies adding them to mods collection
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.ModDiscoverer/INFO]: Found gamelibrary file "mixinextras-neoforge-0.5.4.jar" [parent: neoforge-26.1.2.58-beta-universal.jar, locator: jarinjar, reader: mod manifest]
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.ModDiscoverer/INFO]: Found library file "net.neoforged.neoforge-coremods-26.1.2.58-beta.jar" [parent: neoforge-26.1.2.58-beta-universal.jar, locator: jarinjar, reader: mod manifest]
[08:06:48] [ForkJoinPool.commonPool-worker-2] [net.neoforged.fml.loading.moddiscovery.ModDiscoverer/INFO]: Mod List:
		Name Version (Mod Id)

		Minecraft 26.1.2 (minecraft)
		NeoForge 26.1.2.58-beta (neoforge)
		Retromod 1.0.0-beta.2 (retromod)
[08:06:49] [main] [mixin/INFO]: SpongePowered MIXIN Subsystem Version=0.8.7 Source=file:/D:/AstralRinth%20App/meta/libraries/net/fabricmc/sponge-mixin/0.17.3+mixin.0.8.7/sponge-mixin-0.17.3+mixin.0.8.7.jar Service=FML Env=CLIENT
[08:06:49] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: Loading FML Plugins:
[08:06:49] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: - ~libraries/net/neoforged/neoforge/26.1.2.58-beta/neoforge-26.1.2.58-beta-universal.jar > net.neoforged.neoforge-coremods-26.1.2.58-beta.jar
[08:06:49] [main] [net.neoforged.fml.loading.LanguageProviderLoader/ERROR]: Language loader javafml version 11.0 is incompatible with [26.1,) required by jar(mods/retromod-1.0.0-beta.2+26.1.2.jar)
[08:06:49] [main] [net.neoforged.fml.loading.FMLLoader/INFO]: Closing FML Loader 51b01960
[08:06:49] [main] [net.neoforged.fml.loading.modscan.BackgroundScanHandler/ERROR]: An error occurred scanning file jar(~libraries/net/neoforged/minecraft-client-patched/26.1.2.58-beta/minecraft-client-patched-26.1.2.58-beta.jar)
java.util.concurrent.CancellationException
	at java.base/java.util.concurrent.CompletableFuture.cancel(Unknown Source)
	at net.neoforged.fml.loading.moddiscovery.ModFile.close(ModFile.java:246)
	at net.neoforged.fml.loading.FMLLoader.close(FMLLoader.java:239)
	at net.neoforged.fml.loading.FMLLoader.create(FMLLoader.java:415)
	at net.neoforged.fml.startup.Entrypoint.startup(Entrypoint.java:65)
	at net.neoforged.fml.startup.Client.main(Client.java:17)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(Unknown Source)
	at java.base/java.lang.reflect.Method.invoke(Unknown Source)
	at com.modrinth.theseus.MinecraftLaunch.relaunch(MinecraftLaunch.java:61)
	at com.modrinth.theseus.MinecraftLaunch.main(MinecraftLaunch.java:28)
[08:06:49] [main] [net.neoforged.fml.loading.modscan.BackgroundScanHandler/ERROR]: An error occurred scanning file jar(~libraries/net/neoforged/minecraft-client-patched/26.1.2.58-beta/minecraft-client-patched-26.1.2.58-beta.jar)
[08:06:49] [main] [net.neoforged.fml.ModLoader/INFO]: Clearing ModLoader
[08:06:49] [main] [net.neoforged.fml.startup.Entrypoint/ERROR]: Failed to start FML: net.neoforged.fml.ModLoadingException: Loading errors encountered:
	- Mod File mods/retromod-1.0.0-beta.2+26.1.2.jar needs language provider javafml:26.1 or above to load
	  We have found 11.0

	at net.neoforged.fml.loading.LanguageProviderLoader.findLanguage(LanguageProviderLoader.java:79)
	at net.neoforged.fml.loading.moddiscovery.ModFile.lambda$identifyLanguage$0(ModFile.java:185)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(Unknown Source)
	at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.copyInto(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.evaluate(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.evaluateToArrayNode(Unknown Source)
	at java.base/java.util.stream.ReferencePipeline.toArray(Unknown Source)
	at java.base/java.util.stream.ReferencePipeline.toArray(Unknown Source)
	at java.base/java.util.stream.ReferencePipeline.toList(Unknown Source)
	at net.neoforged.fml.loading.moddiscovery.ModFile.identifyLanguage(ModFile.java:186)
	at net.neoforged.fml.loading.FMLLoader.create(FMLLoader.java:377)
	at net.neoforged.fml.startup.Entrypoint.startup(Entrypoint.java:65)
	at net.neoforged.fml.startup.Client.main(Client.java:17)
	at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(Unknown Source)
	at java.base/java.lang.reflect.Method.invoke(Unknown Source)
	at com.modrinth.theseus.MinecraftLaunch.relaunch(MinecraftLaunch.java:61)
	at com.modrinth.theseus.MinecraftLaunch.main(MinecraftLaunch.java:28)

Gap report (optional but very helpful)

Confirmations

• I checked the Troubleshooting page and didn't find this issue.
• The source mod isn't opted out of Retromod transformation (no META-INF/retromod-opt-out marker in the mod JAR).

[Derpgamer22]

yeah getting this issue too

[Bownlux]

same issue as #9 The "11.0" you're seeing IS your FML
version — that's correct for NeoForge MC 26.1. The bug was Retromod
demanding "26.1+" when it should have demanded "any modern FML."

Fixed in 1.0.0-beta.4. Redownload when it is public and the load should succeed.