diff --git a/office-alexander-logistics-app/src/main/java/com/alexanderlogistics/InvoicePlugin.java b/office-alexander-logistics-app/src/main/java/com/alexanderlogistics/InvoicePlugin.java
index 6b4168d..aadca3d 100644
--- a/office-alexander-logistics-app/src/main/java/com/alexanderlogistics/InvoicePlugin.java
+++ b/office-alexander-logistics-app/src/main/java/com/alexanderlogistics/InvoicePlugin.java
@@ -104,7 +104,7 @@ public class InvoicePlugin extends AbstractPlugin {
         if (isPublicEvent) {
 
             // validate Partner id....
-            if (businessPartner == null) {
+            if (businessPartner == null && isCargoRechnung(workitem)) {
                 String message = resourceBundleHandler.findMessage("ERROR_MISSING_BUSINESSPARTNER");
                 throw new PluginException(InvoicePlugin.class.getName(), ERROR_MISSING_DATA, message);
             }
@@ -424,4 +424,22 @@ public class InvoicePlugin extends AbstractPlugin {
         // Überprüfen, ob das Muster übereinstimmt
         return matcher.matches();
     }
+
+    /**
+     * This method returns true if the current workitem is a Sachrechnung.
+     *
+     * This can be based on different model versions e.g. rechnungseingang-de-1.2,
+     * rechnungseingang-pl-1.0, rechnungseingang-dwc-1.0, ...
+     *
+     * @param workitem
+     * @return
+     */
+    public static boolean isSachrechnungRechnung(ItemCollection workitem) {
+        String REGEX_PATTERN = "rechnungseingang-sachrechnung-([a-z]{2}|[a-z]{3})-\\d.\\d";
+        // Erstellen Sie ein Pattern-Objekt
+        Pattern pattern = Pattern.compile(REGEX_PATTERN);
+        Matcher matcher = pattern.matcher(workitem.getModelVersion());
+        // Überprüfen, ob das Muster übereinstimmt
+        return matcher.matches();
+    }
 }