diff --git a/.github/workflows/schemathesis.yaml b/.github/workflows/schemathesis.yaml
index 2d52848..59c4f24 100644
--- a/.github/workflows/schemathesis.yaml
+++ b/.github/workflows/schemathesis.yaml
@@ -9,7 +9,7 @@ jobs:
         with:
           python-version: '3.8'
 
-      - run: pip install schemathesis
+      - run: pip install 'schemathesis>=3.17.3'
 
       - name: "Extract base url from openapi.yaml"
         uses: mikefarah/yq@master
diff --git a/openapi.yaml b/openapi.yaml
index 3465d1e..0710a35 100644
--- a/openapi.yaml
+++ b/openapi.yaml
@@ -51,6 +51,8 @@ paths:
               example:
                 meta_data: { "version": 1, "created": 1627858357549 }
                 series: [[1627250400000, 7866.0], [1627254000000, 7881.0]]
+        "404":
+          description: No data for combination of filter region and resolution or mismatch between *copy parameters
       description: "Zeitreihendaten nach Filter, Region und Auflösung ab Timestamp"
       summary: "Zeitreihendaten"