diff --git a/package-lock.json b/package-lock.json
index 4c843f54..bc422d9c 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -5,9 +5,9 @@
   "requires": true,
   "dependencies": {
     "monaco-editor-core": {
-      "version": "0.11.3",
-      "resolved": "https://registry.npmjs.org/monaco-editor-core/-/monaco-editor-core-0.11.3.tgz",
-      "integrity": "sha512-e6o/TInK+sRgWaWNj8kIaNinfmTC1vQdwF6QUaZ7h0OT+xILM6zxl+4B0imIbKm7iBYSZR2avH8Hbg8h6qQ2+g==",
+      "version": "0.12.0",
+      "resolved": "https://registry.npmjs.org/monaco-editor-core/-/monaco-editor-core-0.12.0.tgz",
+      "integrity": "sha512-wOoEVAoZtrarDRcQC32Fp0ocacpQd6/Nb0FmUZOHeD3swZuPZhDLOxTyoNLjKq3d+h/6g+IARBLnDaLT5OQD4g==",
       "dev": true
     },
     "monaco-languages": {
diff --git a/package.json b/package.json
index 4a0dd7d8..c75d95da 100644
--- a/package.json
+++ b/package.json
@@ -19,7 +19,7 @@
     "url": "https://github.com/Microsoft/monaco-editor/issues"
   },
   "devDependencies": {
-    "monaco-editor-core": "0.11.3",
+    "monaco-editor-core": "0.12.0",
     "monaco-languages": "^1.0.0",
     "monaco-plugin-helpers": "^1.0.2",
     "monaco-typescript": "^3.0.0",
diff --git a/src/languageFeatures.ts b/src/languageFeatures.ts
index 1a3620de..44d734b5 100644
--- a/src/languageFeatures.ts
+++ b/src/languageFeatures.ts
@@ -93,14 +93,14 @@ export class DiagnostcsAdapter {
 }
 
 
-function toSeverity(lsSeverity: number): monaco.Severity {
+function toSeverity(lsSeverity: number): monaco.MarkerSeverity {
 	switch (lsSeverity) {
-		case ls.DiagnosticSeverity.Error: return monaco.Severity.Error;
-		case ls.DiagnosticSeverity.Warning: return monaco.Severity.Warning;
-		case ls.DiagnosticSeverity.Information:
-		case ls.DiagnosticSeverity.Hint:
+		case ls.DiagnosticSeverity.Error: return monaco.MarkerSeverity.Error;
+		case ls.DiagnosticSeverity.Warning: return monaco.MarkerSeverity.Warning;
+		case ls.DiagnosticSeverity.Information: return monaco.MarkerSeverity.Info;
+		case ls.DiagnosticSeverity.Hint: return monaco.MarkerSeverity.Hint;
 		default:
-			return monaco.Severity.Info;
+			return monaco.MarkerSeverity.Info;
 	}
 }