diff --git a/docs/antrea-network-policy.md b/docs/antrea-network-policy.md
index 7e76d9caf02..6bd66b069e1 100644
--- a/docs/antrea-network-policy.md
+++ b/docs/antrea-network-policy.md
@@ -29,6 +29,8 @@
   - [The ClusterGroup resource](#the-clustergroup-resource)
   - [kubectl commands for ClusterGroup](#kubectl-commands-for-clustergroup)
 - [Select Namespace by Name](#select-namespace-by-name)
+  - [K8s clusters with version 1.21 and above](#k8s-clusters-with-version-121-and-above)
+  - [K8s clusters with version 1.20 and below](#k8s-clusters-with-version-120-and-below)
 - [RBAC](#rbac)
 - [Notes](#notes)
 <!-- /toc -->
@@ -835,8 +837,47 @@ The following kubectl commands can be used to retrieve CG resources:
 Kubernetes NetworkPolicies and Antrea-native policies allow selecting
 workloads from Namespaces with the use of a label selector (i.e. `namespaceSelector`).
 However, it is often desirable to be able to select Namespaces directly by their `name`
-as opposed to using the `labels` associated with the Namespaces. In order to select
-Namespaces by name, Antrea labels Namespaces with a reserved label `antrea.io/metadata.name`,
+as opposed to using the `labels` associated with the Namespaces.
+
+### K8s clusters with version 1.21 and above
+
+Starting with K8s v1.21, all Namespaces are labeled with the `kubernetes.io/metadata.name: <namespaceName>` [label](https://kubernetes.io/docs/concepts/overview/working-with-objects/namespaces/#automatic-labelling)
+provided that the `NamespaceDefaultLabelName` feature gate (enabled by default) is not disabled in K8s.
+K8s NetworkPolicy and Antrea-native policy users can take advantage of this reserved label
+to select Namespaces directly by their `name` in `namespaceSelectors` as follows:
+
+```yaml
+apiVersion: crd.antrea.io/v1alpha1
+kind: NetworkPolicy
+metadata:
+  name: test-anp-by-name
+  namespace: default
+spec:
+    priority: 5
+    tier: application
+    appliedTo:
+      - podSelector: {}
+    egress:
+      - action: Allow
+        to:
+          - podSelector:
+              matchLabels:
+                app: core-dns
+            namespaceSelector:
+              matchLabels:
+                kubernetes.io/metadata.name: kube-system
+        ports:
+          - protocol: TCP
+            port: 53
+        name: AllowToCoreDNS
+```
+
+**Note**: `NamespaceDefaultLabelName` feature gate is scheduled to be removed in K8s v1.24, thereby
+ensuring that labeling Namespaces by their name cannot be disabled.
+
+### K8s clusters with version 1.20 and below
+
+In order to select Namespaces by name, Antrea labels Namespaces with a reserved label `antrea.io/metadata.name`,
 whose value is set to the Namespace's name. Users can then use this label in the
 `namespaceSelector` field, in both K8s NetworkPolicies and Antrea-native policies to
 select Namespaces by name. By default, Namespaces are not labeled with the reserved name label.
@@ -903,13 +944,6 @@ spec:
 The above example allows all Pods from Namespace "default" to connect to all "core-dns"
 Pods from Namespace "kube-system" on TCP port 53.
 
-**Note**: A similar [effort](https://github.com/kubernetes/enhancements/tree/master/keps/sig-api-machinery/2161-apiserver-default-labels) is currently underway in Kubernetes to label all Namespaces
-with `kubernetes.io/metadata.name: <namespaceName>` label. By introducing the
-`antrea.io/metadata.name` label, we give our users early access to this feature.
-When `kubernetes.io/metadata.name` is introduced upstream, we recommend updating
-your policies to use the new label, but we will also keep providing our custom
-admission controller for backwards-compatibility.
-
 ## RBAC
 
 Antrea-native policy CRDs are meant for admins to manage the security of their