diff --git a/4.2.4-Header-Editor.md b/4.2.4-Header-Editor.md
index 8e70d8b..e11373e 100644
--- a/4.2.4-Header-Editor.md
+++ b/4.2.4-Header-Editor.md
@@ -19,7 +19,7 @@ Execute type: Custom function
 
 Code:
 ```js
-for (let a in val) {
+for (const a in val) {
     if (val[a].name.toLowerCase() === 'etag') { val[a].value = ''; }
 }
 ```