Using BlockFluidClassic seems to cause a crash on servers

java.lang.NoClassDefFoundError: net/minecraft/util/EnumWorldBlockLayer

I can't see anything in my blocks code causing it so is it BlockFluidClassic that is not meant to be used?

 

My Block

package epicarno.mystical.common.block;

import java.util.Random;

import epicarno.mystical.common.mystical_epicarno_mod;
import net.minecraft.block.Block;
import net.minecraft.block.material.Material;
import net.minecraft.block.state.IBlockState;
import net.minecraft.util.BlockPos;
import net.minecraft.util.EnumParticleTypes;
import net.minecraft.world.IBlockAccess;
import net.minecraft.world.World;
import net.minecraftforge.fluids.BlockFluidClassic;
import net.minecraftforge.fluids.Fluid;
import net.minecraftforge.fml.common.registry.GameRegistry;
import net.minecraftforge.fml.relauncher.Side;
import net.minecraftforge.fml.relauncher.SideOnly;

public class BlockEpicarnoLiquid extends BlockFluidClassic {

   
        private String name = "MoonWaterBlock";

	public BlockEpicarnoLiquid(Fluid fluid, Material material) {
                super(fluid, material);
            	GameRegistry.registerBlock(this, name);
            	setUnlocalizedName(name );
              //  setCreativeTab(mystical_epicarno_mod.EpicarnoThings);
        }
       
	   

    

        @Override
        public boolean canDisplace(IBlockAccess world, BlockPos pos) {
                if (( world.getBlockState(pos)).getBlock().getMaterial().isLiquid()) return false;
                return super.canDisplace(world,pos);
        }
       
        @Override
        public boolean displaceIfPossible(World world,BlockPos pos) {
                if (( world.getBlockState(pos)).getBlock().getMaterial().isLiquid()) return false;
                return super.displaceIfPossible(world, pos);
        }
       
}

Didn't include enough of the crash report to say that that class is the problem.

 

Because I don't see EnumWorldBlockLayer as being A Thing That Exists, nor used anywhere in the BlockFluidClassic hierarchy.

I was able to fix the crash by making a custom version of BlockFluidBase.

EnumWorldBlockLayer is in BlockFluidBase that BlockFluidClassic extends

It seemed to be missing a @SideOnly(Side.Client)