I am the designated DNS Directorate reviewer for draft-ietf-dnsop-zoneversion. This is the second review I am doing - my last review on the -02 version only identified a few nits. The draft is going to be published as Informational RFC. The document is well written and defines an EDNS option which can be used for debugging purposes.

There was sufficient discussion on the mailing list and significant changes were made (compared to the -02 version) in order to make it more readable. Overall I think the document is ready for publication.