Appears that 1.19.4 +fabric has an issue, crashes before GUI opens:

java.lang.RuntimeException: Could not execute entrypoint stage 'main' due to errors, provided by 'simplylight'!
at net.fabricmc.loader.impl.entrypoint.EntrypointUtils.lambda$invoke0$0(EntrypointUtils.java:51)
at net.fabricmc.loader.impl.util.ExceptionUtil.gatherExceptions(ExceptionUtil.java:33)
at net.fabricmc.loader.impl.entrypoint.EntrypointUtils.invoke0(EntrypointUtils.java:49)
at net.fabricmc.loader.impl.entrypoint.EntrypointUtils.invoke(EntrypointUtils.java:35)
at net.fabricmc.loader.impl.game.minecraft.Hooks.startClient(Hooks.java:52)
at net.minecraft.class_310.(class_310.java:468)
at net.minecraft.client.main.Main.main(Main.java:198)
at net.fabricmc.loader.impl.game.minecraft.MinecraftGameProvider.launch(MinecraftGameProvider.java:462)
at net.fabricmc.loader.impl.launch.knot.Knot.launch(Knot.java:74)
at net.fabricmc.loader.impl.launch.knot.KnotClient.main(KnotClient.java:23)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:224)
at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:259)
at org.multimc.EntryPoint.listen(EntryPoint.java:143)
at org.multimc.EntryPoint.main(EntryPoint.java:34)
Caused by: java.lang.NoSuchFieldError: field_25108
at com.flanks255.simplylight.SimplyLight.(SimplyLight.java:18)
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:467)
at net.fabricmc.loader.impl.util.DefaultLanguageAdapter.create(DefaultLanguageAdapter.java:50)
at net.fabricmc.loader.impl.entrypoint.EntrypointStorage$NewEntry.getOrCreate(EntrypointStorage.java:117)
at net.fabricmc.loader.impl.entrypoint.EntrypointContainerImpl.getEntrypoint(EntrypointContainerImpl.java:53)
at net.fabricmc.loader.impl.entrypoint.EntrypointUtils.invoke0(EntrypointUtils.java:47)
... 15 more

A detailed walkthrough of the error, its code path and all known details is as follows:

-- Head --
Thread: Render thread
Stacktrace:
at net.fabricmc.loader.impl.entrypoint.EntrypointUtils.lambda$invoke0$0(EntrypointUtils.java:51)
at net.fabricmc.loader.impl.util.ExceptionUtil.gatherExceptions(ExceptionUtil.java:33)
at net.fabricmc.loader.impl.entrypoint.EntrypointUtils.invoke0(EntrypointUtils.java:49)
at net.fabricmc.loader.impl.entrypoint.EntrypointUtils.invoke(EntrypointUtils.java:35)
at net.fabricmc.loader.impl.game.minecraft.Hooks.startClient(Hooks.java:52)
at net.minecraft.class_310.(class_310.java:468)

-- Initialization --
Details:
Modules:
Stacktrace:
at net.minecraft.client.main.Main.main(Main.java:198)
at net.fabricmc.loader.impl.game.minecraft.MinecraftGameProvider.launch(MinecraftGameProvider.java:462)
at net.fabricmc.loader.impl.launch.knot.Knot.launch(Knot.java:74)
at net.fabricmc.loader.impl.launch.knot.KnotClient.main(KnotClient.java:23)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:568)
at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:224)
at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:259)
at org.multimc.EntryPoint.listen(EntryPoint.java:143)
at org.multimc.EntryPoint.main(EntryPoint.java:34)

-- System Details --
Details:
Minecraft Version: 1.19.4
Minecraft Version ID: 1.19.4
Operating System: Linux (amd64) version 4.15.0-206-generic
Java Version: 17.0.6, Private Build
Java VM Version: OpenJDK 64-Bit Server VM (mixed mode, sharing), Private Build
Memory: 164651008 bytes (157 MiB) / 536870912 bytes (512 MiB) up to 1073741824 bytes (1024 MiB)
CPUs: 8
Processor Vendor: AuthenticAMD
Processor Name: AMD FX-8370 Eight-Core Processor
Identifier: AuthenticAMD Family 21 Model 2 Stepping 0
Microarchitecture: Piledriver
Frequency (GHz): -0.00
Number of physical packages: 1
Number of physical CPUs: 8
Number of logical CPUs: 8
Graphics card #0 name: Hawaii XT / Grenada XT [Radeon R9 290X/390X]
Graphics card #0 vendor: Advanced Micro Devices, Inc. [AMD/ATI] (0x1002)
Graphics card #0 VRAM (MB): 264.00
Graphics card #0 deviceId: 0x67b0
Graphics card #0 versionInfo: unknown
Virtual memory max (MB): 28283.24
Virtual memory used (MB): 14835.32
Swap memory total (MB): 16282.00
Swap memory used (MB): 1140.00
JVM Flags: 2 total; -Xms512m -Xmx1024m
Fabric Mods:
audioplayer: AudioPlayer 1.19.4-1.5.0
automated_crafting: Automated Crafting 1.4.8
crowdin-translate: CrowdinTranslate 1.4+1.19.3
libgui: LibGui 7.0.0-beta.2+1.19.4
jankson: Jankson 5.0.1+j1.2.2
blue_endless_jankson: jankson 1.2.2
libninepatch: LibNinePatch 1.2.0
croptopia: Croptopia 2.2.2
com_typesafe_config: config 1.4.1
io_leangen_geantyref_geantyref: geantyref 1.3.11
org_spongepowered_configurate-core: configurate-core 4.1.2
org_spongepowered_configurate-hocon: configurate-hocon 4.1.2
fabric-api: Fabric API 0.76.0+1.19.4
fabric-api-lookup-api-v1: Fabric API Lookup API (v1) 1.6.24+49abcf7ef4
fabric-biome-api-v1: Fabric Biome API (v1) 13.0.6+348a9c64f4
fabric-block-api-v1: Fabric Block API (v1) 1.0.5+e022e5d1f4
fabric-blockrenderlayer-v1: Fabric BlockRenderLayer Registration (v1) 1.1.33+c2e6f674f4
fabric-client-tags-api-v1: Fabric Client Tags 1.0.14+1134c5b8f4
fabric-command-api-v1: Fabric Command API (v1) 1.2.25+f71b366ff4
fabric-commands-v0: Fabric Commands (v0) 0.2.42+df3654b3f4
fabric-containers-v0: Fabric Containers (v0) 0.1.52+df3654b3f4
fabric-content-registries-v0: Fabric Content Registries (v0) 3.5.7+ae0966baf4
fabric-convention-tags-v1: Fabric Convention Tags 1.4.0+9a7c5daaf4
fabric-crash-report-info-v1: Fabric Crash Report Info (v1) 0.2.14+aeb40ebef4
fabric-data-generation-api-v1: Fabric Data Generation API (v1) 11.3.5+5da15ca1f4
fabric-dimensions-v1: Fabric Dimensions API (v1) 2.1.44+7f87f8faf4
fabric-entity-events-v1: Fabric Entity Events (v1) 1.5.12+e45f7c65f4
fabric-events-interaction-v0: Fabric Events Interaction (v0) 0.4.42+a1ccd7bff4
fabric-events-lifecycle-v0: Fabric Events Lifecycle (v0) 0.2.51+df3654b3f4
fabric-game-rule-api-v1: Fabric Game Rule API (v1) 1.0.32+a1ccd7bff4
fabric-item-api-v1: Fabric Item API (v1) 2.1.16+09a3510cf4
fabric-item-group-api-v1: Fabric Item Group API (v1) 3.0.3+043f9acff4
fabric-key-binding-api-v1: Fabric Key Binding API (v1) 1.0.32+c477957ef4
fabric-keybindings-v0: Fabric Key Bindings (v0) 0.2.30+df3654b3f4
fabric-lifecycle-events-v1: Fabric Lifecycle Events (v1) 2.2.14+5da15ca1f4
fabric-loot-api-v2: Fabric Loot API (v2) 1.1.25+75e98211f4
fabric-loot-tables-v1: Fabric Loot Tables (v1) 1.1.29+9e7660c6f4
fabric-message-api-v1: Fabric Message API (v1) 5.1.0+1ee8be40f4
fabric-mining-level-api-v1: Fabric Mining Level API (v1) 2.1.37+49abcf7ef4
fabric-models-v0: Fabric Models (v0) 0.3.29+11ba9c3bf4
fabric-networking-api-v1: Fabric Networking API (v1) 1.2.22+ca5f59aaf4
fabric-networking-v0: Fabric Networking (v0) 0.3.39+df3654b3f4
fabric-object-builder-api-v1: Fabric Object Builder API (v1) 7.0.1+63b515f4f4
fabric-particles-v1: Fabric Particles (v1) 1.0.22+f1e4495bf4
fabric-recipe-api-v1: Fabric Recipe API (v1) 1.0.6+a1ccd7bff4
fabric-registry-sync-v0: Fabric Registry Sync (v0) 2.1.2+a383ab97f4
fabric-renderer-api-v1: Fabric Renderer API (v1) 2.2.4+81e8c576f4
fabric-renderer-indigo: Fabric Renderer - Indigo 1.1.0+81e8c576f4
fabric-renderer-registries-v1: Fabric Renderer Registries (v1) 3.2.37+df3654b3f4
fabric-rendering-data-attachment-v1: Fabric Rendering Data Attachment (v1) 0.3.27+afca2f3ef4
fabric-rendering-fluids-v1: Fabric Rendering Fluids (v1) 3.0.20+f1e4495bf4
fabric-rendering-v0: Fabric Rendering (v0) 1.1.40+df3654b3f4
fabric-rendering-v1: Fabric Rendering (v1) 2.1.0+8f878217f4
fabric-resource-conditions-api-v1: Fabric Resource Conditions API (v1) 2.3.0+e6c7d4eef4
fabric-resource-loader-v0: Fabric Resource Loader (v0) 0.11.0+938a1d56f4
fabric-screen-api-v1: Fabric Screen API (v1) 1.0.44+8c25edb4f4
fabric-screen-handler-api-v1: Fabric Screen Handler API (v1) 1.3.18+5da15ca1f4
fabric-sound-api-v1: Fabric Sound API (v1) 1.0.8+75e98211f4
fabric-transfer-api-v1: Fabric Transfer API (v1) 3.0.1+9003cbe9f4
fabric-transitive-access-wideners-v1: Fabric Transitive Access Wideners (v1) 3.0.2+63b515f4f4
fabricloader: Fabric Loader 0.14.18
indium: Indium 1.0.15+mc1.19.4
iris: Iris 1.5.2
io_github_douira_glsl-transformer: glsl-transformer 2.0.0-pre9
org_anarres_jcpp: jcpp 1.4.14
org_antlr_antlr4-runtime: antlr4-runtime 4.11.1
java: OpenJDK 64-Bit Server VM 17
lithium: Lithium 0.11.1
minecraft: Minecraft 1.19.4
phosphor: Phosphor 0.8.1
simplylight: Simply Light 1.19-1.4.3
sodium: Sodium 0.4.10+build.24
terrablender: TerraBlender 2.2.0.154
com_electronwill_night-config_core: core 3.6.4
com_electronwill_night-config_toml: toml 3.6.4
voicechat: Simple Voice Chat 1.19.4-rc3-2.3.28
fabric-api-base: Fabric API Base 0.4.23+9ff28bced8
fabric-command-api-v2: Fabric Command API (v2) 2.2.4+ae0966bad8
worldedit: WorldEdit 7.2.14+6360-094b734
Launched Version: 1.19.4
Backend library: LWJGL version 3.3.1 SNAPSHOT
Backend API: Unknown
Window size:
GL Caps: Using framebuffer using OpenGL 3.2
GL debug messages:
Using VBOs: Yes
Is Modded: Definitely; Client brand changed to 'fabric'
Type: Client (map_client.txt)
CPU:

Ya, the current version only works on 1.19.0, 1.19.1, and 1.19.2, im working on the 1.19.3 version atm, then ill see if it works on .4 as well, or if it needs its own version.

1.19.3 / 1.19.4 version out. Curseforge