When i apply a core file on the k8s cluster with the following contents in the core file:

kubernetes zonename in-addr.arpa ip6.arpa {
transfer to *
upstream
fallthrough in-addr.arpa ip6.arpa
} 
k8s_external zonename 
{
transfer to *
}

Im getting the error in log files of CoreDns Pod:

plugin/k8s_external: /etc/coredns/Corefile:8 - Error during parsing: unknown >property 'transfer'

Looks like this was working in earlier versions. What has changed?

I had used the exact same core file configuration 3 months back and everything looked fine but now when i redeploy im facing this issue.

Expecting CoreDNS pod to start without any errors! May be the syantax or usage of K8s_external plugin has changed?