diff --git a/docs/tasks/upgrading/upgrading-0.8-0.9.rst b/docs/tasks/upgrading/upgrading-0.8-0.9.rst
index 9404a17c8..77f5f0805 100644
--- a/docs/tasks/upgrading/upgrading-0.8-0.9.rst
+++ b/docs/tasks/upgrading/upgrading-0.8-0.9.rst
@@ -2,4 +2,17 @@
 Upgrading from v0.8 to v0.9
 ===========================
 
-There are no special notes or considerations when upgrading from v0.8 to v0.9.
+Due to a change in the API group that cert-manager deployments use
+(`apps/v1beta1` to `apps/v1`), cert-manager deployments must first be deleted
+before applying the new version. This will cause downtime until the new version
+has been applied. To perform this action run:
+
+.. code-block:: shell
+
+   kubectl delete deployments --namespace cert-manager \
+     cert-manager \
+     cert-manager-cainjector \
+     cert-manager-webhook
+
+After this operation, follow the standard upgrade process as defined in the
+:doc:`upgrade guide <./index>`.