org.bukkit.event.EventException: null
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:320) ~[spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:70) ~[spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:529) ~[spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:514) ~[spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at net.minecraft.server.v1_15_R1.PlayerConnection.a(PlayerConnection.java:2391) ~[spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at net.minecraft.server.v1_15_R1.PacketPlayInUpdateSign.a(SourceFile:44) ~[spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at net.minecraft.server.v1_15_R1.PacketPlayInUpdateSign.a(SourceFile:10) ~[spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at net.minecraft.server.v1_15_R1.PlayerConnectionUtils.lambda$0(PlayerConnectionUtils.java:19) ~[spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at net.minecraft.server.v1_15_R1.TickTask.run(SourceFile:18) [spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at net.minecraft.server.v1_15_R1.IAsyncTaskHandler.executeTask(SourceFile:144) [spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at net.minecraft.server.v1_15_R1.IAsyncTaskHandlerReentrant.executeTask(SourceFile:23) [spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at net.minecraft.server.v1_15_R1.IAsyncTaskHandler.executeNext(SourceFile:118) [spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at net.minecraft.server.v1_15_R1.MinecraftServer.aZ(MinecraftServer.java:917) [spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at net.minecraft.server.v1_15_R1.MinecraftServer.executeNext(MinecraftServer.java:910) [spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at net.minecraft.server.v1_15_R1.IAsyncTaskHandler.awaitTasks(SourceFile:127) [spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at net.minecraft.server.v1_15_R1.MinecraftServer.sleepForTick(MinecraftServer.java:894) [spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at net.minecraft.server.v1_15_R1.MinecraftServer.run(MinecraftServer.java:827) [spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]
        at java.lang.Thread.run(Thread.java:829) [?:?]
Caused by: java.lang.NoSuchMethodError: 'int org.bukkit.World.getMinHeight()'
        at net.TheDgtl.Stargate.util.SpawnDetectionHelper.isInterferingWithSpawnProtection(SpawnDetectionHelper.java:37) ~[?:?]
        at net.TheDgtl.Stargate.util.portal.PortalCreationHelper.tryPortalCreation(PortalCreationHelper.java:148) ~[?:?]
        at net.TheDgtl.Stargate.listener.BlockEventListener.onSignChange(BlockEventListener.java:154) ~[?:?]
        at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:?]
        at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:?]
        at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:?]
        at java.lang.reflect.Method.invoke(Method.java:566) ~[?:?]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:316) ~[spigot-1.15.jar:git-Spigot-3b314f5-e2790ae]