Ultra Hardcore

Calls something that is on Kiln's roadmap. Parts of it may already run.

Evidence

Ran on Kiln's test stand (2026-11-04): UltraHardcoreAdvancementPack did not start: java.lang.NoClassDefFoundError: net/minecraft/network/protocol/common/custom/CustomPacketPayload; UltraHardcoreAdvancementPackClient did not start: java.lang.NoClassDefFoundError: net/minecraft/network/protocol/common/custom/CustomPacketPayload.

What it needs from Kiln

Mixin
net.fabricmc.fabric.api.client.networking.v1.ClientPlayNetworking
net.fabricmc.fabric.api.client.networking.v1.ClientPlayNetworking.Context
net.fabricmc.fabric.api.client.networking.v1.ClientPlayNetworking.PlayPayloadHandler
net.fabricmc.fabric.api.command.v2.CommandRegistrationCallback
net.fabricmc.fabric.api.networking.v1.PayloadTypeRegistry
net.fabricmc.fabric.api.networking.v1.ServerPlayNetworking
net.minecraft.commands.CommandSourceStack
net.minecraft.commands.Commands
net.minecraft.commands.Commands.CommandSelection
net.minecraft.network.protocol.common.custom.CustomPacketPayload
net.minecraft.network.protocol.common.custom.CustomPacketPayload.Type
net.minecraft.network.protocol.common.custom.CustomPacketPayload.TypeAndCodec
net.minecraft.server.MinecraftServer
Minecraft.execute()

On the roadmap: Minecraft's libraries and client API (0.2), Code next to data (0.3), Mixin (0.5)

In the author's words

A progression-based advancement datapack featuring custom ranks, advancement rewards, and challenging progression paths.

Scan

Scanned on 4 November 2026 against Kiln 0.2.0, file ultra-hardcore-advancement-pack-1.0.0.jar. The scan reads the mod's classes; it does not run them.

Reports from players

No reports from players yet.

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