Updated note regarding cert-manager operator about namespaces.

modules/cert-manager-install-cli.adoc

@@ -35,6 +35,25 @@ spec:
   - "cert-manager-operator"
 ----
 
+.. For {cert-manager-operator} v1.15.0 or later, create a YAML file with the following content:
++
+[source, yaml]
+----
+apiVersion: operators.coreos.com/v1
+kind: OperatorGroup
+metadata:
+  name: openshift-cert-manager-operator
+  namespace: cert-manager-operator
+spec:
+  targetNamespaces: []
+  spec: {}
+----
++
+[NOTE]
+====
+Starting from {cert-manager-operator} version 1.15.0, it is recommended to install the Operator using the `AllNamespaces` OLM `installMode`. Older versions can continue using the `SingleNamespace` or `OwnNamespace` OLM `installMode`. Support for `SingleNamespace` and `OwnNamespace` will be deprecated in future versions.
+====
+
 .. Create the `OperatorGroup` object by running the following command:
 +
 [source, terminal]
@@ -59,7 +78,6 @@ spec:
   source: redhat-operators
   sourceNamespace: openshift-marketplace
   installPlanApproval: Automatic
-  startingCSV: cert-manager-operator.v1.13.0
 ----
 
 .. Create the `Subscription` object by running the following command:

modules/cert-manager-install-console.adoc

@@ -35,6 +35,11 @@ See supported {cert-manager-operator} versions in the following "Additional reso
 .. Choose the *Installed Namespace* for the Operator. The default Operator namespace is `cert-manager-operator`.
 +
 If the `cert-manager-operator` namespace does not exist, it is created for you.
++
+[NOTE]
+====
+During the installation, the {product-title}  web console allows you to select between `AllNamespaces` and `SingleNamespace` installation modes. For installations with {cert-manager-operator} version 1.15.0 or later, it is recommended to choose the `AllNamespaces` installation mode. `SingleNamespace` and `OwnNamespace` support will remain for earlier versions but will be deprecated in future versions.
+====
 
 .. Select an *Update approval* strategy.
 +

security/cert_manager_operator/cert-manager-operator-install.adoc

@@ -6,6 +6,11 @@ include::_attributes/common-attributes.adoc[]
 
 toc::[]
 
+[IMPORTANT]
+====
+The {cert-manager-operator} version 1.15 or later supports the `AllNamespaces`, `SingleNamespace`, and `OwnNamespace` installation modes. Earlier versions, such as 1.14, support only the `SingleNamespace` and `OwnNamespace` installation modes.
+====
+
 The {cert-manager-operator} is not installed in {product-title} by default. You can install the {cert-manager-operator} by using the web console.
 
 == Installing the {cert-manager-operator}