diff --git a/packages/decdk/test/fixture/tsconfig.json b/packages/decdk/test/fixture/tsconfig.json
index ff97fed3..07afb1f6 100644
--- a/packages/decdk/test/fixture/tsconfig.json
+++ b/packages/decdk/test/fixture/tsconfig.json
@@ -7,7 +7,7 @@
     "inlineSourceMap": true,
     "inlineSources": true,
     "lib": [
-      "es2016"
+      "es2018"
     ],
     "module": "CommonJS",
     "noEmitOnError": true,
@@ -22,7 +22,7 @@
     "strictNullChecks": true,
     "strictPropertyInitialization": true,
     "stripInternal": true,
-    "target": "ES2017"
+    "target": "ES2018"
   },
   "include": [
     "**/*.ts"