Control Plane Upgrade

You need to perform a canary deployment to upgrade the control plane and label all resources with {revision}, for example, istiod-1-13-9-r5. The sidecar proxies of existing service instances do not communicate with the control plane of the new version, and the upgrade and rollback do not affect the services in the service mesh of the old version. If your control plane is upgraded from a non-canary version to a canary version, the number of istio-operator instances in the old version will be set to 0 during the upgrade.
After the control plane of the new version is installed, an istio-ingressgateway-{revision} instance and an istio-egressgateway-{revision} instance of the Deployment are automatically created. Their labels are the same as those of the old gateway instances.
If you have created an istio-ingressgateway instance in another namespace, the instance will be automatically upgraded to the new version istio-ingressgateway-{revision}-{namespace}. {revision} indicates the version number, for example, 1-13-9-r5. {namespace} indicates the namespace.