Hello there, I found some warnings in game log:

[15:52:51] [main/INFO]: [STDERR]: java.lang.ClassNotFoundException: com.github.draylar.vh.api.HammerItem [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:602) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178) [15:52:51] [main/INFO]: [STDERR]: at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.launch.knot.KnotClassLoader.loadClass(KnotClassLoader.java:161) [15:52:51] [main/INFO]: [STDERR]: at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522) [15:52:51] [main/INFO]: [STDERR]: at java.base/java.lang.Class.forName0(Native Method) [15:52:51] [main/INFO]: [STDERR]: at java.base/java.lang.Class.forName(Class.java:340) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.VanillaHammersIntegration.<clinit>(VanillaHammersIntegration.java:41) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.registry.ItemsRegistry.<clinit>(ItemsRegistry.java:85) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.registry.BlocksRegistry.registerBlock(BlocksRegistry.java:433) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.registry.BlocksRegistry.<clinit>(BlocksRegistry.java:28) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.BetterNether.onInitialize(BetterNether.java:30) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke0(EntrypointUtils.java:50) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke(EntrypointUtils.java:36) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointClient.start(EntrypointClient.java:32) [15:52:51] [main/INFO]: [STDERR]: at net.minecraft.class_310.<init>(class_310.java:425) [15:52:51] [main/INFO]: [STDERR]: at net.minecraft.client.main.Main.main(Main.java:177) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [15:52:51] [main/INFO]: [STDERR]: at java.base/java.lang.reflect.Method.invoke(Method.java:564) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:192) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:140) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:26) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [15:52:51] [main/INFO]: [STDERR]: at java.base/java.lang.reflect.Method.invoke(Method.java:564) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:196) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:231) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.EntryPoint.listen(EntryPoint.java:143) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.EntryPoint.main(EntryPoint.java:34) [15:52:51] [main/INFO]: [STDERR]: java.lang.NullPointerException [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.VanillaHammersIntegration.makeHammer(VanillaHammersIntegration.java:24) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.registry.ItemsRegistry.<clinit>(ItemsRegistry.java:85) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.registry.BlocksRegistry.registerBlock(BlocksRegistry.java:433) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.registry.BlocksRegistry.<clinit>(BlocksRegistry.java:28) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.BetterNether.onInitialize(BetterNether.java:30) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke0(EntrypointUtils.java:50) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke(EntrypointUtils.java:36) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointClient.start(EntrypointClient.java:32) [15:52:51] [main/INFO]: [STDERR]: at net.minecraft.class_310.<init>(class_310.java:425) [15:52:51] [main/INFO]: [STDERR]: at net.minecraft.client.main.Main.main(Main.java:177) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [15:52:51] [main/INFO]: [STDERR]: at java.base/java.lang.reflect.Method.invoke(Method.java:564) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:192) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:140) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:26) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [15:52:51] [main/INFO]: [STDERR]: at java.base/java.lang.reflect.Method.invoke(Method.java:564) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:196) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:231) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.EntryPoint.listen(EntryPoint.java:143) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.EntryPoint.main(EntryPoint.java:34) [15:52:51] [main/INFO]: [STDERR]: java.lang.NullPointerException [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.VanillaHammersIntegration.makeHammer(VanillaHammersIntegration.java:24) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.registry.ItemsRegistry.<clinit>(ItemsRegistry.java:86) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.registry.BlocksRegistry.registerBlock(BlocksRegistry.java:433) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.registry.BlocksRegistry.<clinit>(BlocksRegistry.java:28) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.BetterNether.onInitialize(BetterNether.java:30) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke0(EntrypointUtils.java:50) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke(EntrypointUtils.java:36) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointClient.start(EntrypointClient.java:32) [15:52:51] [main/INFO]: [STDERR]: at net.minecraft.class_310.<init>(class_310.java:425) [15:52:51] [main/INFO]: [STDERR]: at net.minecraft.client.main.Main.main(Main.java:177) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [15:52:51] [main/INFO]: [STDERR]: at java.base/java.lang.reflect.Method.invoke(Method.java:564) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:192) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:140) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:26) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [15:52:51] [main/INFO]: [STDERR]: at java.base/java.lang.reflect.Method.invoke(Method.java:564) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:196) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:231) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.EntryPoint.listen(EntryPoint.java:143) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.EntryPoint.main(EntryPoint.java:34) [15:52:51] [main/INFO]: [STDERR]: java.lang.NullPointerException [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.VanillaHammersIntegration.makeHammer(VanillaHammersIntegration.java:24) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.registry.ItemsRegistry.<clinit>(ItemsRegistry.java:87) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.registry.BlocksRegistry.registerBlock(BlocksRegistry.java:433) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.registry.BlocksRegistry.<clinit>(BlocksRegistry.java:28) [15:52:51] [main/INFO]: [STDERR]: at paulevs.betternether.BetterNether.onInitialize(BetterNether.java:30) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke0(EntrypointUtils.java:50) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke(EntrypointUtils.java:36) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointClient.start(EntrypointClient.java:32) [15:52:51] [main/INFO]: [STDERR]: at net.minecraft.class_310.<init>(class_310.java:425) [15:52:51] [main/INFO]: [STDERR]: at net.minecraft.client.main.Main.main(Main.java:177) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [15:52:51] [main/INFO]: [STDERR]: at java.base/java.lang.reflect.Method.invoke(Method.java:564) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.game.MinecraftGameProvider.launch(MinecraftGameProvider.java:192) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:140) [15:52:51] [main/INFO]: [STDERR]: at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:26) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) [15:52:51] [main/INFO]: [STDERR]: at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) [15:52:51] [main/INFO]: [STDERR]: at java.base/java.lang.reflect.Method.invoke(Method.java:564) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.onesix.OneSixLauncher.launchWithMainClass(OneSixLauncher.java:196) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.onesix.OneSixLauncher.launch(OneSixLauncher.java:231) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.EntryPoint.listen(EntryPoint.java:143) [15:52:51] [main/INFO]: [STDERR]: at org.multimc.EntryPoint.main(EntryPoint.java:34)

Mm, yeah, I basically entirely broke mod compatibility with the latest update (Better Nether is the mod erroring, as they previously reflected into the Vanilla Hammers mod to add hammers). I might be able to send them a fix PR in the next week or so.

OK, thank you for your reply!