diff --git a/ecs/alerts/fields/mapping-settings.json b/ecs/alerts/fields/mapping-settings.json
index 0ad2b48fcc1be..f176a1c52e87f 100644
--- a/ecs/alerts/fields/mapping-settings.json
+++ b/ecs/alerts/fields/mapping-settings.json
@@ -1,4 +1,4 @@
 {
-    "dynamic": "strict",
+    "dynamic": true,
     "date_detection": false
-}
\ No newline at end of file
+}