Upgrade istio 1.3.1 Helm to istio 1.7

Dear Team,

We have planned to upgrade the istio 1.3.1 to istio 1.7.4, which using helm chart deployment file, Need help to upgrade plan documentations.
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Selva@ip-10-44-18-221:~/.kube$ kubectl get deployments -nistio-system

NAME READY UP-TO-DATE AVAILABLE AGE
elasticsearch 0/1 1 0 194d
grafana 1/1 1 1 494d
istio-citadel 1/1 1 1 494d
istio-galley 1/1 1 1 494d
istio-ingressgateway 1/1 1 1 494d
istio-pilot 1/1 1 1 494d
istio-policy 1/1 1 1 494d
istio-pvt-ingressgateway 1/1 1 1 494d
istio-sidecar-injector 1/1 1 1 494d
istio-telemetry 1/1 1 1 494d
istio-tracing 1/1 1 1 494d
kiali 1/1 1 1 494d
kibana 1/1 1 1 192d
prometheus 1/1 1 1 494d
zipkin 1/1 1 1 144d
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Regards,
Selva