Upgrading istio 1.4.3 to 1.6.0

We have istio 1.4.3 running in production and staging both in GKE cluster. It was installed using Helm. We have one external LB and one internal LB. Installing both LB using Helm was pretty straightforward.

But, now Helm install method is deprecated. Can anyone tell me what would be the correct way to upgrade to 1.6.0 with minimal or no downtime. Also, we want keep using both the internal and external LB. Help much appreciated.

Can I upgrade from 1.4.3 directly to 1.6.4? Should I upgrade from 1.4.x to 1.5.x and then from 1.5.x to 1.6x

I still couldn’t find any docs or references that say otherwise. Any input, pointers will be highly appreciated.