diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index 707a7be0f5..7287a8863e 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -4,6 +4,7 @@ Yii Framework 2 Change Log
 2.0.43 under development
 ------------------------
 
+- Bug #18650: Refactor `framework/assets/yii.activeForm.js` arrow function into traditional function for IE11 compatibility (marcovtwout)
 - Enh #18628: Added strings "software", and "hardware" to `$specials` array in `yii\helpers\BaseInflector` (kjusupov)
 
 
diff --git a/framework/assets/yii.activeForm.js b/framework/assets/yii.activeForm.js
index c61df82b27..ab44e0cbd8 100644
--- a/framework/assets/yii.activeForm.js
+++ b/framework/assets/yii.activeForm.js
@@ -329,7 +329,9 @@
                 this.$form = $form;
                 var $input = findInput($form, this);
 
-                var disabled = $input.toArray().reduce((result, next) => result && $(next).is(':disabled'), true);
+                var disabled = $input.toArray().reduce(function(result, next) {
+                    return result && $(next).is(':disabled');
+                }, true);
                 if (disabled) {
                     return true;
                 }