diff --git a/build.gradle b/build.gradle
index f51a54d0f5..0f5bbc7290 100644
--- a/build.gradle
+++ b/build.gradle
@@ -288,7 +288,7 @@ project(':forge') {
         installer 'org.ow2.asm:asm:6.2'
         installer 'org.ow2.asm:asm-commons:6.2'
         installer 'org.ow2.asm:asm-tree:6.2'
-        installer 'cpw.mods:modlauncher:0.11.+'
+        installer 'cpw.mods:modlauncher:0.12.+'
         installer 'net.minecraftforge:accesstransformers:0.15.+:shadowed'
         installer 'net.minecraftforge:eventbus:0.8.+:service'
         installer 'net.minecraftforge:forgespi:0.11.+'
diff --git a/src/main/resources/log4j2.xml b/src/main/resources/log4j2.xml
index c877b733c8..b787260b05 100644
--- a/src/main/resources/log4j2.xml
+++ b/src/main/resources/log4j2.xml
@@ -1,5 +1,21 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Configuration status="warn" packages="net.minecrell.terminalconsole,net.minecrell.terminalconsole.util,com.mojang.util">
+    <filters>
+        <MarkerFilter marker="NETWORK_PACKETS" onMatch="${sys:forge.logging.marker.networking:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="CLASSLOADING" onMatch="${sys:forge.logging.marker.classloading:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="LAUNCHPLUGIN" onMatch="${sys:forge.logging.marker.launchplugin:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="CLASSDUMP" onMatch="${sys:forge.logging.marker.classdump:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="AXFORM" onMatch="${sys:forge.logging.marker.axform:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="EVENTBUS" onMatch="${sys:forge.logging.marker.eventbus:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="DISTXFORM" onMatch="${sys:forge.logging.marker.distxform:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="SCAN" onMatch="${sys:forge.logging.marker.scan:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="REGISTRIES" onMatch="${sys:forge.logging.marker.registries:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="REGISTRYDUMP" onMatch="${sys:forge.logging.marker.registrydump:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="SPLASH" onMatch="${sys:forge.logging.marker.splash:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="FORGEMOD" onMatch="${sys:forge.logging.marker.forgemod:-ACCEPT}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="LOADING" onMatch="${sys:forge.logging.marker.loading:-ACCEPT}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="CORE" onMatch="${sys:forge.logging.marker.core:-ACCEPT}" onMismatch="NEUTRAL"/>
+    </filters>
     <Appenders>
         <TerminalConsole name="Console">
             <PatternLayout>
@@ -39,22 +55,8 @@
         <!-- make sure mojang's logging is set to 'info' so that their LOGGER.isDebugEnabled() behavior isn't active -->
         <Logger level="${sys:forge.logging.mojang.level:-info}" name="com.mojang"/>
         <Logger level="${sys:forge.logging.mojang.level:-info}" name="net.minecraft"/>
+        <Logger level="${sys:forge.logging.classtransformer.level:-info}" name="cpw.mods.modlauncher.ClassTransformer"/>
         <Root level="all">
-            <filters>
-                <MarkerFilter marker="NETWORK_PACKETS" onMatch="${sys:forge.logging.marker.networking:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="CLASSLOADING" onMatch="${sys:forge.logging.marker.classloading:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="LAUNCHPLUGIN" onMatch="${sys:forge.logging.marker.launchplugin:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="AXFORM" onMatch="${sys:forge.logging.marker.axform:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="EVENTBUS" onMatch="${sys:forge.logging.marker.eventbus:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="DISTXFORM" onMatch="${sys:forge.logging.marker.distxform:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="SCAN" onMatch="${sys:forge.logging.marker.scan:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="REGISTRIES" onMatch="${sys:forge.logging.marker.registries:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="REGISTRYDUMP" onMatch="${sys:forge.logging.marker.registrydump:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="SPLASH" onMatch="${sys:forge.logging.marker.splash:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="FORGEMOD" onMatch="${sys:forge.logging.marker.forgemod:-ACCEPT}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="LOADING" onMatch="${sys:forge.logging.marker.loading:-ACCEPT}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="CORE" onMatch="${sys:forge.logging.marker.core:-ACCEPT}" onMismatch="NEUTRAL"/>
-            </filters>
             <AppenderRef ref="Console" level="${sys:forge.logging.console.level:-info}"/>
             <AppenderRef ref="ServerGuiConsole" level="${sys:forge.logging.console.level:-info}"/>
             <AppenderRef ref="File" level="${sys:forge.logging.file.level:-info}"/>
diff --git a/src/main/resources/log4j2_server.xml b/src/main/resources/log4j2_server.xml
index 737cdfedd6..b475688c2d 100644
--- a/src/main/resources/log4j2_server.xml
+++ b/src/main/resources/log4j2_server.xml
@@ -1,5 +1,21 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Configuration status="warn" packages="net.minecrell.terminalconsole,net.minecrell.terminalconsole.util,com.mojang.util">
+    <filters>
+        <MarkerFilter marker="NETWORK_PACKETS" onMatch="${sys:forge.logging.marker.networking:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="CLASSLOADING" onMatch="${sys:forge.logging.marker.classloading:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="LAUNCHPLUGIN" onMatch="${sys:forge.logging.marker.launchplugin:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="CLASSDUMP" onMatch="${sys:forge.logging.marker.classdump:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="AXFORM" onMatch="${sys:forge.logging.marker.axform:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="EVENTBUS" onMatch="${sys:forge.logging.marker.eventbus:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="DISTXFORM" onMatch="${sys:forge.logging.marker.distxform:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="SCAN" onMatch="${sys:forge.logging.marker.scan:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="REGISTRIES" onMatch="${sys:forge.logging.marker.registries:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="REGISTRYDUMP" onMatch="${sys:forge.logging.marker.registrydump:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="SPLASH" onMatch="${sys:forge.logging.marker.splash:-DENY}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="FORGEMOD" onMatch="${sys:forge.logging.marker.forgemod:-ACCEPT}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="LOADING" onMatch="${sys:forge.logging.marker.loading:-ACCEPT}" onMismatch="NEUTRAL"/>
+        <MarkerFilter marker="CORE" onMatch="${sys:forge.logging.marker.core:-ACCEPT}" onMismatch="NEUTRAL"/>
+    </filters>
     <Appenders>
         <TerminalConsole name="Console">
             <PatternLayout>
@@ -39,22 +55,8 @@
         <!-- make sure mojang's logging is set to 'info' so that their LOGGER.isDebugEnabled() behavior isn't active -->
         <Logger level="${sys:forge.logging.mojang.level:-info}" name="com.mojang"/>
         <Logger level="${sys:forge.logging.mojang.level:-info}" name="net.minecraft"/>
+        <Logger level="${sys:forge.logging.classtransformer.level:-info}" name="cpw.mods.modlauncher.ClassTransformer"/>
         <Root level="all">
-            <filters>
-                <MarkerFilter marker="NETWORK_PACKETS" onMatch="${sys:forge.logging.marker.networking:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="CLASSLOADING" onMatch="${sys:forge.logging.marker.classloading:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="LAUNCHPLUGIN" onMatch="${sys:forge.logging.marker.launchplugin:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="AXFORM" onMatch="${sys:forge.logging.marker.axform:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="EVENTBUS" onMatch="${sys:forge.logging.marker.eventbus:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="DISTXFORM" onMatch="${sys:forge.logging.marker.distxform:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="SCAN" onMatch="${sys:forge.logging.marker.scan:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="REGISTRIES" onMatch="${sys:forge.logging.marker.registries:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="REGISTRYDUMP" onMatch="${sys:forge.logging.marker.registrydump:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="SPLASH" onMatch="${sys:forge.logging.marker.splash:-DENY}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="FORGEMOD" onMatch="${sys:forge.logging.marker.forgemod:-ACCEPT}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="LOADING" onMatch="${sys:forge.logging.marker.loading:-ACCEPT}" onMismatch="NEUTRAL"/>
-                <MarkerFilter marker="CORE" onMatch="${sys:forge.logging.marker.core:-ACCEPT}" onMismatch="NEUTRAL"/>
-            </filters>
             <AppenderRef ref="Console" level="${sys:forge.logging.console.level:-info}"/>
             <AppenderRef ref="ServerGuiConsole" level="${sys:forge.logging.console.level:-info}"/>
             <AppenderRef ref="File" level="${sys:forge.logging.file.level:-info}"/>
diff --git a/src/userdev/java/net/minecraftforge/userdev/UserdevLauncher.java b/src/userdev/java/net/minecraftforge/userdev/UserdevLauncher.java
index 0a1f7ab15e..6afc266975 100644
--- a/src/userdev/java/net/minecraftforge/userdev/UserdevLauncher.java
+++ b/src/userdev/java/net/minecraftforge/userdev/UserdevLauncher.java
@@ -23,6 +23,7 @@ import com.google.common.base.Strings;
 import com.google.common.collect.ObjectArrays;
 import cpw.mods.modlauncher.Launcher;
 import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.MarkerManager;
 import org.apache.logging.log4j.core.Filter;
 import org.apache.logging.log4j.core.LoggerContext;
 import org.apache.logging.log4j.core.config.Configurator;
@@ -37,7 +38,10 @@ public class UserdevLauncher
     public static void main(String... args) throws InterruptedException
     {
         final String markerselection = System.getProperty("forge.logging.markers", "");
-        Arrays.stream(markerselection.split(",")).forEach(marker-> System.setProperty("forge.logging.marker."+ marker.toLowerCase(Locale.ROOT), "ACCEPT"));
+        Arrays.stream(markerselection.split(",")).forEach(marker-> {
+            System.setProperty("forge.logging.marker." + marker.toLowerCase(Locale.ROOT), "ACCEPT");
+            MarkerManager.getMarker(marker.toUpperCase(Locale.ROOT));
+        });
 
         String assets = System.getenv().getOrDefault("assetDirectory", "assets");
         String target = System.getenv().get("target");