Update release notes for Private PDF Document Generation Service

Author: samuelreichert

content/en/docs/releasenotes/marketplace/marketplace-services/private-service.md

@@ -7,7 +7,13 @@ weight: 20
 numberless_headings: true
 ---
 
-## 1.0.3 (`latest`)
+## 1.0.4 (`latest`)
+
+**Release date: May 18, 2026**
+
+This release includes routine security updates, which do not pose any apparent risk to Mendix customers.
+
+## 1.0.3
 
 **Release date: March 06, 2026**