I know you are unlikely to provide any support for a that old Minecraft version, but I wanted to try nontheless.
DoubleSlabs Versions higher than 0.10.0 crash the server directly on boot if CraftTweaker, SecurityCraft or RailCraft is installed:
---- Minecraft Crash Report ----
// Daisy, daisy...
Time: 2026-02-26 16:51:52 CET
Description: Exception in server tick loop
java.lang.NoSuchMethodError: net.minecraft.item.Item.func_190903_i()Lnet/minecraft/item/ItemStack;
at cjminecraft.doubleslabs.common.items.VerticalSlabItem.lambda$getSubItems$1(VerticalSlabItem.java:59)
at java.lang.Iterable.forEach(Iterable.java:75)
at cjminecraft.doubleslabs.common.items.VerticalSlabItem.getSubItems(VerticalSlabItem.java:53)
at crafttweaker.mc1120.item.MCItemUtils.createItemList(MCItemUtils.java:53)
at crafttweaker.mc1120.brackets.BracketHandlerItem.rebuildItemRegistry(BracketHandlerItem.java:63)
at crafttweaker.mc1120.events.CommonEventHandler.registerRecipes(CommonEventHandler.java:60)
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_851_CommonEventHandler_registerRecipes_Register.invoke(.dynamic)
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90)
at net.minecraftforge.fml.common.eventhandler.EventBus$1.invoke(EventBus.java:144)
at net.minecraftforge.fml.common.eventhandler.EventBus.forgeBridge$post(EventBus.java:759)
at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:706)
at net.minecraftforge.registries.GameData.fireRegistryEvents(GameData.java:857)
at net.minecraftforge.common.crafting.CraftingHelper.loadRecipes(CraftingHelper.java:636)
at net.minecraftforge.fml.common.Loader.initializeMods(Loader.java:747)
at net.minecraftforge.fml.server.FMLServerHandler.finishServerLoading(FMLServerHandler.java:108)
at net.minecraftforge.fml.common.FMLCommonHandler.onServerStarted(FMLCommonHandler.java:338)
at net.minecraft.server.dedicated.DedicatedServer.init(DedicatedServer.java:219)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:486)
at java.lang.Thread.run(Thread.java:750)
and (if Craft Tweaker is removed, which triggers before this can trigger)
---- Minecraft Crash Report ----
// Hey, that tickles! Hehehe!
Time: 2026-02-26 17:02:44 CET
Description: Exception in server tick loop
net.minecraftforge.fml.common.LoaderExceptionModCrash: Caught exception from Railcraft (railcraft)
Caused by: net.minecraft.util.ReportedException: Loading Railcraft Module
at mods.railcraft.common.modules.RailcraftModuleManager.processStage(RailcraftModuleManager.java:257)
at mods.railcraft.common.modules.RailcraftModuleManager.init(RailcraftModuleManager.java:227)
at mods.railcraft.common.core.Railcraft.init(Railcraft.java:133)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at net.minecraftforge.fml.common.FMLModContainer.handleModStateEvent(FMLModContainer.java:637)
at sun.reflect.GeneratedMethodAccessor10.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.google.common.eventbus.Subscriber.invokeSubscriberMethod(Subscriber.java:91)
at com.google.common.eventbus.Subscriber$SynchronizedSubscriber.invokeSubscriberMethod(Subscriber.java:150)
at com.google.common.eventbus.Subscriber$1.run(Subscriber.java:76)
at com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:399)
at com.google.common.eventbus.Subscriber.dispatchEvent(Subscriber.java:71)
at com.google.common.eventbus.Dispatcher$PerThreadQueuedDispatcher.dispatch(Dispatcher.java:116)
at com.google.common.eventbus.EventBus.post(EventBus.java:217)
at net.minecraftforge.fml.common.LoadController.sendEventToModContainer(LoadController.java:219)
at net.minecraftforge.fml.common.LoadController.propogateStateMessage(LoadController.java:197)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.google.common.eventbus.Subscriber.invokeSubscriberMethod(Subscriber.java:91)
at com.google.common.eventbus.Subscriber$SynchronizedSubscriber.invokeSubscriberMethod(Subscriber.java:150)
at com.google.common.eventbus.Subscriber$1.run(Subscriber.java:76)
at com.google.common.util.concurrent.MoreExecutors$DirectExecutor.execute(MoreExecutors.java:399)
at com.google.common.eventbus.Subscriber.dispatchEvent(Subscriber.java:71)
at com.google.common.eventbus.Dispatcher$PerThreadQueuedDispatcher.dispatch(Dispatcher.java:116)
at com.google.common.eventbus.EventBus.post(EventBus.java:217)
at net.minecraftforge.fml.common.LoadController.redirect$zza000$forgeImpl$PostEvent(LoadController.java:568)
at net.minecraftforge.fml.common.LoadController.distributeStateMessage(LoadController.java:136)
at net.minecraftforge.fml.common.Loader.initializeMods(Loader.java:749)
at net.minecraftforge.fml.server.FMLServerHandler.finishServerLoading(FMLServerHandler.java:108)
at net.minecraftforge.fml.common.FMLCommonHandler.onServerStarted(FMLCommonHandler.java:338)
at net.minecraft.server.dedicated.DedicatedServer.init(DedicatedServer.java:219)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:486)
at java.lang.Thread.run(Thread.java:750)
Caused by: java.lang.NoSuchMethodError: net.minecraft.item.Item.func_190903_i()Lnet/minecraft/item/ItemStack;
at cjminecraft.doubleslabs.common.items.VerticalSlabItem.lambda$getSubItems$1(VerticalSlabItem.java:59)
at java.lang.Iterable.forEach(Iterable.java:75)
at cjminecraft.doubleslabs.common.items.VerticalSlabItem.getSubItems(VerticalSlabItem.java:53)
at mods.railcraft.common.fluids.FluidContainerHandler.init(FluidContainerHandler.java:40)
at mods.railcraft.common.fluids.FluidContainerHandler.findCanDrain(FluidContainerHandler.java:51)
at mods.railcraft.common.util.crafting.FluidIngredient.<init>(FluidIngredient.java:41)
at mods.railcraft.common.util.crafting.Ingredients.from(Ingredients.java:40)
at mods.railcraft.common.plugins.forge.CraftingPlugin.cleanRecipeArray(CraftingPlugin.java:91)
at mods.railcraft.common.plugins.forge.CraftingPlugin.processRecipe(CraftingPlugin.java:116)
at mods.railcraft.common.plugins.forge.CraftingPlugin.makeShapedRecipe(CraftingPlugin.java:179)
at mods.railcraft.common.plugins.forge.CraftingPlugin.addShapedRecipe(CraftingPlugin.java:136)
at mods.railcraft.common.plugins.forge.CraftingPlugin.addShapedRecipe(CraftingPlugin.java:121)
at mods.railcraft.common.items.ItemTie.defineRecipes(ItemTie.java:42)
at java.util.Optional.ifPresent(Optional.java:159)
at mods.railcraft.common.core.IRailcraftObjectContainer.defineRecipes(IRailcraftObjectContainer.java:148)
at mods.railcraft.common.modules.RailcraftModulePayload$BaseModuleEventHandler.lambda$init$1(RailcraftModulePayload.java:90)
at java.lang.Iterable.forEach(Iterable.java:75)
at mods.railcraft.common.modules.RailcraftModulePayload$BaseModuleEventHandler.init(RailcraftModulePayload.java:87)
at mods.railcraft.common.modules.RailcraftModuleManager$Stage$3.passToModule(RailcraftModuleManager.java:351)
at mods.railcraft.common.modules.RailcraftModuleManager.processStage(RailcraftModuleManager.java:244)
... 38 more
There seems to be a hint to the cause here: CraftTweaker/CraftTweaker#1781
DoubleSlabs Version 0.10.0 and lower cause area based ticking related crashes that brick the player as they get them whenever they login once they have them:
---- Minecraft Crash Report ----
// I feel sad now :(
Time: 2026-02-26 04:37:45 CET
Description: Exception ticking world
java.lang.NullPointerException
at org.spongepowered.common.bridge.data.DataCompoundHolder.data$getSpongeCompound(DataCompoundHolder.java:42)
at net.minecraft.tileentity.TileEntity.handler$zla000$sponge$impl$WriteSpongeDataToCompound(TileEntity.java:3708)
at net.minecraft.tileentity.TileEntity.writeToNBT(TileEntity.java)
at cjminecraft.doubleslabs.tileentitiy.TileEntityVerticalSlab.writeToNBT(TileEntityVerticalSlab.java:153)
at cjminecraft.doubleslabs.tileentitiy.TileEntityDoubleSlab.writeToNBT(TileEntityDoubleSlab.java:36)
at cjminecraft.doubleslabs.tileentitiy.TileEntityDoubleSlab.getTileData(TileEntityDoubleSlab.java:77)
at net.minecraft.tileentity.TileEntity.data$getRootCompound(TileEntity.java:5170)
at org.spongepowered.common.bridge.data.DataCompoundHolder.data$getSpongeCompound(DataCompoundHolder.java:41)
at net.minecraft.tileentity.TileEntity.handler$zla000$sponge$impl$WriteSpongeDataToCompound(TileEntity.java:3708)
at net.minecraft.tileentity.TileEntity.writeToNBT(TileEntity.java)
at cjminecraft.doubleslabs.tileentitiy.TileEntityVerticalSlab.writeToNBT(TileEntityVerticalSlab.java:153)
at cjminecraft.doubleslabs.tileentitiy.TileEntityDoubleSlab.writeToNBT(TileEntityDoubleSlab.java:36)
at cjminecraft.doubleslabs.tileentitiy.TileEntityVerticalSlab.getUpdateTag(TileEntityVerticalSlab.java:173)
at cjminecraft.doubleslabs.tileentitiy.TileEntityDoubleSlab.getUpdateTag(TileEntityDoubleSlab.java:51)
at net.minecraft.network.play.server.SPacketChunkData.<init>(SourceFile:52)
at net.minecraft.server.management.PlayerChunkMapEntry.sendToPlayers(PlayerChunkMapEntry.java:157)
at net.minecraft.server.management.PlayerChunkMap.tick(SourceFile:165)
at net.minecraft.world.WorldServer.tick(WorldServer.java:227)
at net.minecraft.server.MinecraftServer.updateTimeLightAndEntities(MinecraftServer.java:756)
at net.minecraft.server.dedicated.DedicatedServer.updateTimeLightAndEntities(DedicatedServer.java:397)
at net.minecraft.server.MinecraftServer.tick(MinecraftServer.java:668)
at net.minecraft.server.MinecraftServer.run(MinecraftServer.java:526)
at java.lang.Thread.run(Thread.java:750)
That means that none of the available versions for 1.12.2 work - which is a pity.
I know you are unlikely to provide any support for a that old Minecraft version, but I wanted to try nontheless.
DoubleSlabs Versions higher than 0.10.0 crash the server directly on boot if CraftTweaker, SecurityCraft or RailCraft is installed:
and (if Craft Tweaker is removed, which triggers before this can trigger)
There seems to be a hint to the cause here: CraftTweaker/CraftTweaker#1781
DoubleSlabs Version 0.10.0 and lower cause area based ticking related crashes that brick the player as they get them whenever they login once they have them:
That means that none of the available versions for 1.12.2 work - which is a pity.