After June 27th, any glue records which remain pointed to our old name server IP addresses will result in an interruption of your DNS service.
This change will force all DNS queries to be directed through CloudFlare. On June 27th, our DNS infrastructure will cease to answer DNS queries which are received on our old name server IP addresses. This upcoming change is the final step in a recent series of efforts to engineer a more resilient DNS service. The new architecture will isolate our authoritative name servers behind an edge layer, which will handle all contact with public traffic. Our old name server IP addresses will continue to be available at this edge layer to process zone transfers, but queries will need to be directed to our new name server IP addresses, which carry requests over the CloudFlare network.