diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index dacc670e..9231d7fb 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -191,6 +191,31 @@ jobs:
       - name: Template validation
         run: helm template kates charts/kates/ > /dev/null
 
+      # The backup CronJob dumps only the bundled PostgreSQL. values-prod.yaml
+      # set backup.enabled with externalDatabase and rendered no backup,
+      # silently. Assert the prod overlay renders and that the combination is
+      # refused.
+      - name: Assert backup needs the bundled database
+        run: |
+          helm template kates charts/kates/ \
+            -f charts/kates/values-prod.yaml \
+            --set externalDatabase.existingSecret=ci > /dev/null
+          if out=$(helm template kates charts/kates/ \
+               --set backup.enabled=true \
+               --set postgresql.enabled=false \
+               --set externalDatabase.enabled=true \
+               --set externalDatabase.host=db \
+               --set externalDatabase.password=x 2>&1); then
+            echo "::error::backup.enabled with postgresql.enabled=false rendered; it must fail"
+            exit 1
+          fi
+          # Any other failure would pass the check above without testing it.
+          if ! grep -q 'backup.enabled: the backup CronJob dumps the bundled PostgreSQL' <<< "$out"; then
+            echo "::error::the render failed, but not on the backup check: $out"
+            exit 1
+          fi
+          echo "OK: backup without the bundled database is refused"
+
       # The Strimzi version is declared in five places. If values.yaml's
       # strimziVersion drifts from the Chart.yaml dependency version, the CRD
       # hook applies CRDs for a different operator than the one installed —
diff --git a/README.md b/README.md
index 75cd1c36..7811f203 100644
--- a/README.md
+++ b/README.md
@@ -213,7 +213,7 @@ When you install charts with Helm directly:
 | [`kafka-ui`](charts/kafka-ui/) | 0.3.0 | v1.5.0 | A Helm chart for deploying Kafka UI (Kafbat) with Strimzi SCRAM-SHA-512 authentication |
 | [`kates-chaos`](charts/kates-chaos/) | 2.2.1 | 3.28.0 | Kates Chaos Engineering — wraps the LitmusChaos execution plane (operator, exporter, CRDs) with Kafka-specific RBAC, experiment/engine templating, and monitoring |
 | [`kates-platform`](charts/kates-platform/) | 0.7.0 | 1.0.0 | Umbrella chart for the full Kates platform — Kafka, Kates, and supporting infrastructure |
-| [`kates`](charts/kates/) | 0.10.11 | 1.25.1 | Kates — Kafka Advanced Testing & Engineering Suite |
+| [`kates`](charts/kates/) | 0.11.0 | 1.25.1 | Kates — Kafka Advanced Testing & Engineering Suite |
 | [`legacy-kafka`](charts/legacy-kafka/) | 0.2.0 | 3.9.1 | A deliberately old Kafka (2.x on ZooKeeper, or 3.x on KRaft) to migrate FROM — the replication source that the pinned Strimzi release cannot deploy |
 | [`mirror-maker2`](charts/mirror-maker2/) | 0.11.4 | 4.3.1 | Strimzi KafkaMirrorMaker2 — cross-cluster replication, DR, and cross-version migration (2.x/3.x → 4.x) |
 | [`monitoring`](charts/monitoring/) | 1.6.0 | 82.4.3 | Kates Monitoring — wraps kube-prometheus-stack with Kates-specific dashboards and configuration |
diff --git a/charts/kates/Chart.yaml b/charts/kates/Chart.yaml
index caf1ec4d..ffb23c05 100644
--- a/charts/kates/Chart.yaml
+++ b/charts/kates/Chart.yaml
@@ -2,11 +2,11 @@ apiVersion: v2
 name: kates
 description: Kates — Kafka Advanced Testing & Engineering Suite
 type: application
-# Patch: the test run cleanup CronJob deletes runs at last, through the
-# API's DELETE /api/tests with the apiKey Secret's key, and cleanup.statuses
-# picks which finished runs it deletes. appVersion is unchanged; the job
-# takes an image newer than it.
-version: 0.10.11
+# Minor: backup.enabled without the bundled PostgreSQL now fails rendering,
+# where it rendered no backup and said nothing, and values-prod.yaml drops its
+# backup block. A failed pg_dump fails the backup job before the prune and
+# leaves no archive. appVersion is unchanged.
+version: 0.11.0
 # The non-blocking health endpoints this chart's probes now point at come from
 # a BUILD-TIME property (quarkus.messaging.health.enabled=false), so they only
 # exist in the image built from this branch. Keep appVersion and
@@ -30,6 +30,8 @@ annotations:
   artifacthub.io/category: integration-delivery
   artifacthub.io/license: Apache-2.0
   artifacthub.io/changes: |
+    - kind: fixed
+      description: "ACTION REQUIRED for values that set backup.enabled with externalDatabase — those backups never ran. The backup CronJob dumps the bundled PostgreSQL only and rendered only with postgresql.enabled, so values-prod.yaml's backup block (and the README's production example) rendered no CronJob and no PVC, while NOTES printed a backup schedule. backup.enabled without postgresql.enabled now fails rendering; back the external database up with its own tooling and set backup.enabled=false. values-prod.yaml no longer sets it. A pg_dump that failed also left a valid, empty gzip archive, the job passed, and the prune then deleted the real backups. The script runs with set -eo pipefail and dumps to a .partial file it renames only once the dump succeeds, so a failed dump fails the job before the prune and leaves no archive behind"
     - kind: changed
       description: "appVersion 1.25.1 and the image tag move to 1.25.1, the release of the deployment hardening in #368: engine timeout and reaper tunables wired through values and the configmap, stranded runs recovered more robustly, and network policy updates. Templates are otherwise unchanged."
     - kind: fixed
diff --git a/charts/kates/README.md b/charts/kates/README.md
index e7907b62..1b8aeaac 100644
--- a/charts/kates/README.md
+++ b/charts/kates/README.md
@@ -194,7 +194,7 @@ that — `image.tag` does.
 
 | Parameter | Default | Description |
 |-----------|---------|-------------|
-| `backup.enabled` | `false` | Enable PostgreSQL backup CronJob |
+| `backup.enabled` | `false` | Enable PostgreSQL backup CronJob (bundled PostgreSQL only; rendering fails with `postgresql.enabled=false`) |
 | `backup.schedule` | `0 2 * * *` | Backup cron schedule |
 | `backup.retention` | `7` | Days to keep backups |
 | `backup.persistence.enabled` | `false` | Use PVC instead of emptyDir |
@@ -256,7 +256,6 @@ helm install kates ./charts/kates \
   --set networkPolicy.enabled=true \
   --set metrics.serviceMonitor.enabled=true \
   --set metrics.prometheusRule.enabled=true \
-  --set backup.enabled=true \
   --set cleanup.enabled=true
 ```
 
diff --git a/charts/kates/templates/backup-cronjob.yaml b/charts/kates/templates/backup-cronjob.yaml
index 425bc8ba..d2e2716a 100644
--- a/charts/kates/templates/backup-cronjob.yaml
+++ b/charts/kates/templates/backup-cronjob.yaml
@@ -1,4 +1,5 @@
-{{- if and .Values.backup.enabled .Values.postgresql.enabled }}
+{{- if .Values.backup.enabled }}
+{{- if not .Values.postgresql.enabled }}{{- fail "backup.enabled: the backup CronJob dumps the bundled PostgreSQL (postgresql.enabled) only, so with externalDatabase no backup would run. Back the external database up with its own tooling and set backup.enabled=false." }}{{- end }}
 apiVersion: batch/v1
 kind: CronJob
 metadata:
@@ -31,14 +32,22 @@ spec:
               - sh
               - -c
               - |
+                # Without pipefail a failed pg_dump still left gzip's valid,
+                # empty archive, the job passed, and the prune below deleted
+                # the real backups. The dump is written as .partial and named
+                # only once it succeeds, so a failed try (OnFailure retries in
+                # the same pod) leaves no archive a restore would pick.
+                set -eo pipefail
                 TIMESTAMP=$(date +%Y%m%d-%H%M%S)
                 FILENAME="/backups/kates-${TIMESTAMP}.sql.gz"
+                rm -f /backups/kates-*.sql.gz.partial
                 echo "Starting backup to ${FILENAME}..."
                 pg_dump -h {{ include "kates.postgresql.fullname" . }} \
                   -U "${PGUSER}" \
                   -d "${PGDATABASE}" \
                   --no-password \
-                  | gzip > "${FILENAME}"
+                  | gzip > "${FILENAME}.partial"
+                mv "${FILENAME}.partial" "${FILENAME}"
                 echo "Backup complete: $(du -sh ${FILENAME})"
                 echo "Pruning backups older than {{ .Values.backup.retention }} days..."
                 find /backups -name "kates-*.sql.gz" -mtime +{{ .Values.backup.retention }} -delete
diff --git a/charts/kates/values-prod.yaml b/charts/kates/values-prod.yaml
index 10413b6d..7a20dd40 100644
--- a/charts/kates/values-prod.yaml
+++ b/charts/kates/values-prod.yaml
@@ -73,13 +73,10 @@ externalDatabase:
   # your secrets operator:
   # existingSecret: "kates-db-credentials"
 
-backup:
-  enabled: true
-  schedule: "0 1 * * *"
-  retention: 30
-  persistence:
-    enabled: true
-    size: 50Gi
+# No backup block: the chart's backup dumps only the bundled PostgreSQL, which
+# productionMode refuses. Back the external database up with its own tooling
+# (CloudNativePG backups, a managed service's point-in-time recovery); see the
+# externalDatabase comment in values.yaml.
 
 cleanup:
   enabled: true
diff --git a/charts/kates/values.yaml b/charts/kates/values.yaml
index 1554ec55..a7deb651 100644
--- a/charts/kates/values.yaml
+++ b/charts/kates/values.yaml
@@ -674,7 +674,9 @@ tests:
 
 # -- PostgreSQL backup CronJob
 backup:
-  # -- Enable backup CronJob
+  # -- Enable backup CronJob. It dumps the bundled PostgreSQL only, so
+  # rendering fails with postgresql.enabled=false: back an external database
+  # up with its own tooling.
   enabled: false
   # -- Cron schedule expression
   schedule: "0 2 * * *"
diff --git a/docs/book/appendix-d-versions.md b/docs/book/appendix-d-versions.md
index 37f3f255..3d70f79c 100644
--- a/docs/book/appendix-d-versions.md
+++ b/docs/book/appendix-d-versions.md
@@ -22,7 +22,7 @@ Every version the platform pins, in one place. This table is generated from the
 | `kafka-ui` chart | 0.3.0 (app v1.5.0) | `charts/kafka-ui/Chart.yaml` |
 | `kates-chaos` chart | 2.2.1 (app 3.28.0) | `charts/kates-chaos/Chart.yaml` |
 | `kates-platform` chart | 0.7.0 (app 1.0.0) | `charts/kates-platform/Chart.yaml` |
-| `kates` chart | 0.10.11 (app 1.25.1) | `charts/kates/Chart.yaml` |
+| `kates` chart | 0.11.0 (app 1.25.1) | `charts/kates/Chart.yaml` |
 | `legacy-kafka` chart | 0.2.0 (app 3.9.1) | `charts/legacy-kafka/Chart.yaml` |
 | `mirror-maker2` chart | 0.11.4 (app 4.3.1) | `charts/mirror-maker2/Chart.yaml` |
 | `monitoring` chart | 1.6.0 (app 82.4.3) | `charts/monitoring/Chart.yaml` |