diff --git a/administrator/components/com_fields/src/Model/FieldModel.php b/administrator/components/com_fields/src/Model/FieldModel.php
index 1b8031d1042b7..d21983578d4df 100644
--- a/administrator/components/com_fields/src/Model/FieldModel.php
+++ b/administrator/components/com_fields/src/Model/FieldModel.php
@@ -617,6 +617,13 @@ public function setFieldValue($fieldId, $itemId, $value)
             return false;
         }
 
+        if (!is_numeric($itemId)) {
+            @trigger_error(
+                'Using non-numeric IDs for content items for custom fields is deprecated. Convert your extension to only use numeric IDs.',
+                E_USER_DEPRECATED
+            );
+        }
+
         $needsDelete = false;
         $needsInsert = false;
         $needsUpdate = false;