diff --git a/src/maploader/compatibility.cpp b/src/maploader/compatibility.cpp
index e59357731..461f8cab4 100644
--- a/src/maploader/compatibility.cpp
+++ b/src/maploader/compatibility.cpp
@@ -353,21 +353,18 @@ IMPLEMENT_CLASS(DLevelCompatibility, true, false);
 
 void MapLoader::SetCompatibilityParams(FName checksum)
 {
-	if (checksum != NAME_None)
+	auto lc = Create<DLevelCompatibility>();
+	lc->loader = this;
+	lc->Level = Level;
+	for(auto cls : PClass::AllClasses)
 	{
-		auto lc = Create<DLevelCompatibility>();
-		lc->loader = this;
-		lc->Level = Level;
-		for(auto cls : PClass::AllClasses)
+		if (cls->IsDescendantOf(RUNTIME_CLASS(DLevelCompatibility)))
 		{
-			if (cls->IsDescendantOf(RUNTIME_CLASS(DLevelCompatibility)))
+			PFunction *const func = dyn_cast<PFunction>(cls->FindSymbol("Apply", false));
+			if (func != nullptr)
 			{
-				PFunction *const func = dyn_cast<PFunction>(cls->FindSymbol("Apply", false));
-				if (func != nullptr)
-				{
-					VMValue param[] = { lc, (int)checksum };
-					VMCall(func->Variants[0].Implementation, param, 2, nullptr, 0);
-				}
+				VMValue param[] = { lc, checksum.GetIndex(), &Level->MapName };
+				VMCall(func->Variants[0].Implementation, param, 3, nullptr, 0);
 			}
 		}
 	}
diff --git a/wadsrc/static/zscript/level_compatibility.txt b/wadsrc/static/zscript/level_compatibility.txt
index 29378b01e..25eacb9da 100644
--- a/wadsrc/static/zscript/level_compatibility.txt
+++ b/wadsrc/static/zscript/level_compatibility.txt
@@ -3,10 +3,13 @@ class LevelCompatibility native play
 {
 	native LevelLocals level;
 	
-	protected void Apply(Name checksum)
+	protected void Apply(Name checksum, String mapname)
 	{
 		switch (checksum)
 		{			
+			case 'none':
+				return;
+				
 			case '9BC9E12781903D7C2D5697A5E0AEFD6F': // HACX.WAD map05 from 21.10.2010
 			case '9527DD0809FDA39CCFC316A21D135783': // HACX.WAD map05 from 20.10.2010
 			{