Linode API - RDNS

I realize that this is a really stale question, but I want to respond because this post came up in my search results.

It is possible to set the RDNS in APIv3 using the linoode.ip.setrdns api_action.

The modern APIv4 approach is to PUT the RDNS name into the IP address, as described here, https://developers.linode.com/api/v4#operation/updateIP

curl -H "Content-Type: application/json" \
    -H "Authorization: Bearer $TOKEN" \
    -X PUT -d '{
      "rdns": "test.example.org"
    }' \
    https://api.linode.com/v4/networking/ips/97.107.143.141