Migration Path for Upgrading a Causal Cluster on Google's Kubernetes Marketplace

I currently have a causal cluster deployed from Google's Kubernetes Marketplace, via the neo4j-3.5 chart.

Is the upgrade path for clusters deployed via the GKM documented anywhere? I haven't been able to find any good information as to whether this possible / how difficult it will be to migrate the present 3.5 cluster to a 4.x version, though I'd like to begin planning the process so as not to fall increasingly behind the improvements / updates in 4.x.

I'd greatly appreciate any information / context along these lines.