Mobility Modifications

Evidence

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

What it needs from Kiln

• net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents
• net.fabricmc.fabric.api.client.networking.v1.ClientPlayConnectionEvents.Join
• 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.event.lifecycle.v1.ServerTickEvents
• net.fabricmc.fabric.api.event.lifecycle.v1.ServerTickEvents.EndTick
• net.fabricmc.fabric.api.networking.v1.PayloadTypeRegistry
• net.fabricmc.fabric.api.networking.v1.ServerPlayNetworking
• net.fabricmc.fabric.api.networking.v1.ServerPlayNetworking.Context
• net.fabricmc.fabric.api.networking.v1.ServerPlayNetworking.PlayPayloadHandler
• net.minecraft.client.Options
• net.minecraft.core.particles.BlockParticleOption
• net.minecraft.core.particles.ParticleOptions
• net.minecraft.core.particles.ParticleTypes
• net.minecraft.network.codec.ByteBufCodecs
• net.minecraft.network.codec.StreamCodec
• 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
• net.minecraft.server.players.PlayerList
• net.minecraft.util.Mth
• net.minecraft.world.effect.MobEffectInstance
• net.minecraft.world.effect.MobEffects
• net.minecraft.world.entity.EquipmentSlot
• net.minecraft.world.entity.Pose
• net.minecraft.world.food.FoodData
• net.minecraft.world.phys.AABB
• net.minecraft.world.phys.shapes.VoxelShape
• KeyMapping.isDown()
• Minecraft.options
• LocalPlayer.getDeltaMovement()
• LocalPlayer.getEffect()
• LocalPlayer.getFoodData()
• LocalPlayer.getItemBySlot()
• LocalPlayer.getLookAngle()
• LocalPlayer.getPose()
• LocalPlayer.horizontalCollision
• LocalPlayer.isFallFlying()
• and 25 more

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

In the author's words

Adds more than just running and jumping! (Dashing, Wall jumping, Climbing, Crawling)

Scan

Scanned on 4 November 2026 against Kiln 0.2.0, file mobilitymodifications-1.0.0+mc-26.3.jar. The scan reads the mod's classes; it does not run them.