diff --git a/docs/install/installing-istio.md b/docs/install/installing-istio.md
index 5efd3797af..91b9aa2377 100644
--- a/docs/install/installing-istio.md
+++ b/docs/install/installing-istio.md
@@ -112,11 +112,14 @@ need to update gateway configmap `config-istio` under the `knative-serving` name
     kubectl edit configmap config-istio -n knative-serving
     ```
 
-2. Replace the `local-gateway.knative-serving.knative-local-gateway` field with the custom service. As an example, if you name both
+2. Replace the `local-gateways` field with the custom service. As an example, if you name both
 the service and deployment `custom-local-gateway` under the namespace `istio-system`, it should be updated to:
 
     ```
-    custom-local-gateway.istio-system.svc.cluster.local
+    local-gateways: |
+      - name: knative-local-gateway
+        namespace: knative-serving
+        service: custom-local-gateway.istio-system.svc.cluster.local
     ```
 
 As an example, if both the custom service and deployment are labeled with `custom: custom-local-gateway`, not the default
diff --git a/docs/install/operator/configuring-serving-cr.md b/docs/install/operator/configuring-serving-cr.md
index 2eeb996dd7..79b12b4ef3 100644
--- a/docs/install/operator/configuring-serving-cr.md
+++ b/docs/install/operator/configuring-serving-cr.md
@@ -312,10 +312,19 @@ spec:
               istio: ingressgateway
       config:
         istio:
-          gateway.knative-serving.knative-ingress-gateway: "custom-ingressgateway.custom-ns.svc.cluster.local"
+          external-gateways: |
+            - name: knative-ingress-gateway
+              namespace: knative-serving
+              service: custom-ingressgateway.custom-ns.svc.cluster.local
     ```
 
-    The key in `spec.config.istio` is in the format of `gateway.<gateway_namespace>.<gateway_name>`.
+    The key in `spec.config.istio` is in the format of
+    ```
+    external-gateways: |
+      - name: <gateway_name>
+        namespace: <gateway_namespace>
+        service: istio-ingressgateway.istio-system.svc.cluster.local
+    ```
 
 ## Replace the ingress gateway
 
@@ -332,10 +341,19 @@ spec:
     spec:
       config:
         istio:
-          gateway.custom-ns.knative-custom-gateway: "istio-ingressgateway.istio-system.svc.cluster.local"
+          external-gateways: |
+            - name: knative-custom-gateway
+              namespace: custom-ns
+              service: istio-ingressgateway.istio-system.svc.cluster.local
     ```
 
-    The key in `spec.config.istio` is in the format of `gateway.<gateway_namespace>.<gateway_name>`.
+    The key in `spec.config.istio` is in the format of
+    ```
+    external-gateways: |
+      - name: <gateway_name>
+        namespace: <gateway_namespace>
+        service: istio-ingressgateway.istio-system.svc.cluster.local
+    ```
 
 ## Configuration of cluster local gateway
 
@@ -369,7 +387,10 @@ spec:
           custom: custom-local-gateway
   config:
     istio:
-      local-gateway.knative-serving.knative-local-gateway: "custom-local-gateway.istio-system.svc.cluster.local"
+      local-gateways: |
+        - name: knative-local-gateway
+          namespace: knative-serving
+          service: custom-local-gateway.istio-system.svc.cluster.local
 ```
 
 ## Servers configuration for Istio gateways:
@@ -400,7 +421,10 @@ spec:
           - <test-ip>
   config:
     istio:
-      local-gateway.knative-serving.knative-local-gateway: "custom-local-gateway.istio-system.svc.cluster.local"
+      local-gateways: |
+        - name: knative-local-gateway
+          namespace: knative-serving
+          service: custom-local-gateway.istio-system.svc.cluster.local
 ```
 
 ## Customize kourier-bootstrap for Kourier gateways:
diff --git a/docs/install/operator/knative-with-operators.md b/docs/install/operator/knative-with-operators.md
index 9075d4a93b..dd844c97d5 100644
--- a/docs/install/operator/knative-with-operators.md
+++ b/docs/install/operator/knative-with-operators.md
@@ -161,7 +161,10 @@ Knative Serving with different ingresses:
               # ...
               config:
                 istio:
-                  local-gateway.<local-gateway-namespace>.knative-local-gateway: "knative-local-gateway.<istio-namespace>.svc.cluster.local"
+                  local-gateways: |
+                    - name: knative-local-gateway
+                      namespace: <local-gateway-namespace>
+                      service: knative-local-gateway.<istio-namespace>.svc.cluster.local
             ```
 
             Where:
diff --git a/docs/serving/setting-up-custom-ingress-gateway.md b/docs/serving/setting-up-custom-ingress-gateway.md
index 39b0fbe795..86664dbad0 100644
--- a/docs/serving/setting-up-custom-ingress-gateway.md
+++ b/docs/serving/setting-up-custom-ingress-gateway.md
@@ -72,17 +72,22 @@ namespace:
          #                              #
          ################################
          # ...
-         gateway.knative-serving.knative-ingress-gateway: "istio-ingressgateway.istio-system.svc.cluster.local"
+         external-gateways: |
+           - name: knative-ingress-gateway
+             namespace: knative-serving
+             service: istio-ingressgateway.istio-system.svc.cluster.local
      ```
 
-1. Edit the file to add the `gateway.knative-serving.knative-ingress-gateway: <ingress_name>.<ingress_namespace>.svc.cluster.local` field with
-the fully qualified url of your service.
+1. Edit the file to add the `external-gateways` field with the fully qualified url of your service.
 For the example `custom-ingressgateway` service mentioned earlier, it should be updated to:
 
      ```yaml
      apiVersion: v1
      data:
-       gateway.knative-serving.knative-ingress-gateway: custom-ingressgateway.custom-ns.svc.cluster.local
+       external-gateways: |
+         - name: knative-ingress-gateway
+           namespace: knative-serving
+           service: custom-ingressgateway.custom-ns.svc.cluster.local
      kind: ConfigMap
      [...]
      ```
@@ -147,21 +152,30 @@ namespace:
          #                              #
          ################################
          # ...
-         gateway.knative-serving.knative-ingress-gateway: "istio-ingressgateway.istio-system.svc.cluster.local"
+         external-gateways: |
+           - name: knative-ingress-gateway
+             namespace: knative-serving
+             service: istio-ingressgateway.istio-system.svc.cluster.local
      ```
 
-1. Edit the file to add the `gateway.<gateway-namespace>.<gateway-name>: istio-ingressgateway.istio-system.svc.cluster.local` field with
-the customized gateway.
+1. Edit the file to add the `external-gateways` field with the customized gateway.
 For the example `knative-custom-gateway` mentioned earlier, it should be updated to:
 
      ```yaml
      apiVersion: v1
      data:
-       gateway.custom-ns.knative-custom-gateway: "istio-ingressgateway.istio-system.svc.cluster.local"
+       external-gateways: |
+         - name: knative-custom-gateway
+           namespace: custom-ns
+           service: istio-ingressgateway.istio-system.svc.cluster.local
      kind: ConfigMap
      [...]
      ```
 
-The configuration format should be `gateway.<gateway-namespace>.<gateway-name>`.
-`<gateway-namespace>` is optional. When it is omitted, the system searches for
-the gateway in the serving system namespace `knative-serving`.
+The configuration format should be
+```
+  external-gateways: |
+    - name: <gateway-name>
+      namespace: <gateway-namespace>
+      service: <fully-qualified-url-of-istio-ingress-service>
+```