diff --git a/lib/Fhp/FinTs.php b/lib/Fhp/FinTs.php
index e69ef2af..bd0f6d6e 100644
--- a/lib/Fhp/FinTs.php
+++ b/lib/Fhp/FinTs.php
@@ -375,6 +375,16 @@ private function processServerResponse(BaseAction $action, Message $response): v
         if ($action instanceof PaginateableAction && $action->hasMorePages()) {
             $this->execute($action);
         }
+
+        // Check whether the server requested a Kundensystem-ID refresh.
+        if ($response->findRueckmeldung(Rueckmeldungscode::NEUE_KUNDENSYSTEM_ID_HOLEN) !== null) {
+            // TODO Properly implement the refresh here, see https://github.com/nemiah/phpFinTS/issues/458.
+            $this->logger->warning(
+                'The server asked us to refresh the Kundensystem-ID in response to a ' . gettype($action) .
+                ' action, but that is not implemented yet. This could result in authentication errors or extraneous ' .
+                ' re-authentication prompts from the bank.'
+            );
+        }
     }
 
     /**
diff --git a/lib/Fhp/Segment/HIRMS/Rueckmeldungscode.php b/lib/Fhp/Segment/HIRMS/Rueckmeldungscode.php
index 8136e0d3..d401cbbb 100644
--- a/lib/Fhp/Segment/HIRMS/Rueckmeldungscode.php
+++ b/lib/Fhp/Segment/HIRMS/Rueckmeldungscode.php
@@ -2,6 +2,8 @@
 
 namespace Fhp\Segment\HIRMS;
 
+use Fhp\Protocol\DialogInitialization;
+
 /**
  * Enum for the response codes that the server can send.
  *
@@ -128,6 +130,12 @@ public static function isError(int $code): bool
      */
     public const TEILWEISE_FEHLERHAFT = 9050;
 
+    /**
+     * Neue Kundensystem-ID anfordern.
+     * Als Antwort auf eine Dialoginitialisierungsnachricht ({@link DialogInitialization}).
+     */
+    public const NEUE_KUNDENSYSTEM_ID_HOLEN = 9391;
+
     /**
      * Kreditinstitutsseitige Beendigung des Dialoges
      */