diff --git a/k8s/README.md b/k8s/README.md
index 05663e4..636a34e 100644
--- a/k8s/README.md
+++ b/k8s/README.md
@@ -22,6 +22,16 @@ NAMESPACE="datalab"
 kubectl patch deployment $DEPLOYMENT -n $NAMESPACE -p "{\"spec\": {\"template\": {\"metadata\": { \"labels\": {  \"redeploy\": \"$( date +%s )\"}}}}}"
 ```
 
+## helm modify release data
+
+```sh
+# see https://gist.github.com/DzeryCZ/c4adf39d4a1a99ae6e594a183628eaee
+kubectl get secret sh.helm.release.v1.mailu.v8 -n mailu -o json | jq .data.release | tr -d '"' | base64 -d | base64 -d | gzip -d > tmp_v8_mailu
+# edit as you like
+kubcetl edit -n mailu secret sh.helm.release.v1.mailu.v8
+# delete the "release" stuff and copy and paste :)
+```
+
 # Deployment (non persistent stuff)
 
 ## [ingress-nginx](https://github.com/kubernetes/ingress-nginx/tree/master/charts/ingress-nginx)
@@ -446,9 +456,34 @@ Using the [mailu helm chart](https://github.com/Mailu/helm-charts/tree/master/ma
 ```sh
 helm repo add mailu https://mailu.github.io/helm-charts/
 helm repo update
+kubectl apply -f mailu/mailu.secret-key.secret.yml
 helm upgrade --install mailu mailu/mailu -n mailu -f mailu/mailu.secret.yml
 #helm upgrade --install mailu ../../mailu-helm-charts/mailu/ -n mailu -f mailu/mailu.secret.yml
-helm template mailu ../../mailu-helm-charts/mailu/ -n mailu -f mailu/mailu.secret.yml
+helm template mailu mailu/mailu -n mailu -f mailu/mailu.secret.yml
+#helm template mailu ../../mailu-helm-charts/mailu/ -n mailu -f mailu/mailu.secret.yml
+```
+
+## SECRET_KEY
+
+There was an ERROR as follows:
+
+```sh
+ERROR:root:Can't read SECRET_KEY from file: expected str, bytes or os.PathLike object, not NoneType
+Traceback (most recent call last):
+  File "/config.py", line 8, in <module>
+    system.set_env()
+  File "/app/venv/lib/python3.10/site-packages/socrate/system.py", line 35, in set_env
+    raise exc
+  File "/app/venv/lib/python3.10/site-packages/socrate/system.py", line 32, in set_env
+    secret_key = open(os.environ.get("SECRET_KEY_FILE"), "r").read().strip()
+TypeError: expected str, bytes or os.PathLike object, not NoneTypew
+```
+
+The fix was to add the env variable as follows to the failing deployments:
+
+```sh
+          - name: SECRET_KEY
+            value: "fa5faeD9aegietaesahbiequ5Pe9au"
 ```
 
 ### troubleshooting
diff --git a/k8s/mailu/mailu.secret.yml b/k8s/mailu/mailu.secret.yml
index a04f5c3..df15970 100644
--- a/k8s/mailu/mailu.secret.yml
+++ b/k8s/mailu/mailu.secret.yml
@@ -1,4 +1,7 @@
-mailuVersion: master
+# DO NOT USE MASTER!!!!
+#mailuVersion: master
+# DO NOT USE MASTER!!!
+
 hostnames: 
     - mail.moritzgraf.de
 domain: moritzgraf.de