diff --git a/addons/xterm-addon-attach/src/tsconfig.json b/addons/xterm-addon-attach/src/tsconfig.json
index d875aa53..5539aa56 100644
--- a/addons/xterm-addon-attach/src/tsconfig.json
+++ b/addons/xterm-addon-attach/src/tsconfig.json
@@ -1,7 +1,7 @@
 {
   "compilerOptions": {
     "module": "commonjs",
-    "target": "es2015",
+    "target": "es5",
     "lib": [
       "dom",
       "es2015"