diff --git a/guides/services/constraints.md b/guides/services/constraints.md
index aaa6b0db5..01f855d88 100644
--- a/guides/services/constraints.md
+++ b/guides/services/constraints.md
@@ -368,13 +368,9 @@ service Sue {
}
```
-In addition to server-side input validation as introduced above, this adds a corresponding `@FieldControl` annotation to the EDMX so that OData / Fiori clients would enforce a valid entry, thereby avoiding unnecessary request roundtrips:
-
-```xml
-
-
-
-```
+::: warning Deep updates not covered
+`@mandatory` validation is **not** applied to nested data in deep update operations. To enforce mandatory values in those cases, use the [`not null` constraint](../../cds/cdl#constraints) instead.
+:::