diff --git a/helm/mail/templates/statefulset.yaml b/helm/mail/templates/statefulset.yaml
index 7b3ef7e..4ef5ad7 100644
--- a/helm/mail/templates/statefulset.yaml
+++ b/helm/mail/templates/statefulset.yaml
@@ -221,7 +221,9 @@ spec:
         {{- if .Values.extraVolumes }}{{- toYaml .Values.extraVolumes | nindent 8 }}{{ end }}
   {{- if and .Values.persistence.enabled (not .Values.persistence.existingClaim) }}
   volumeClaimTemplates:
-    - metadata:
+    - apiVersion: v1
+      kind: PersistentVolumeClaim
+      metadata:
         name: {{ $fullName }}
         namespace: {{ .Release.Namespace }}
       spec: