diff --git a/README.md b/README.md
index f52134df2c3..5d4e61f149a 100644
--- a/README.md
+++ b/README.md
@@ -27,7 +27,7 @@ Network Policies in a very efficient manner.
 
 ## Prerequisites
 
-Antrea has been tested with Kubernetes clusters running version 1.16 or later.
+Antrea has been tested with Kubernetes clusters running version 1.19 or later.
 
 * `NodeIPAMController` must be enabled in the Kubernetes cluster.\
   When deploying a cluster with kubeadm the `--pod-network-cidr <cidr>`
diff --git a/pkg/apiserver/handlers/webhook/convert_crd.go b/pkg/apiserver/handlers/webhook/convert_crd.go
index 930789bd525..54170d6f4a3 100644
--- a/pkg/apiserver/handlers/webhook/convert_crd.go
+++ b/pkg/apiserver/handlers/webhook/convert_crd.go
@@ -24,6 +24,7 @@ import (
 
 	"github.com/munnerz/goautoneg"
 	v1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
+	// Deprecated: apiextensions/v1beta1 is deprecated, use apiextensions/v1 instead
 	"k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1beta1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"