[knot-dns-users] Audit the consistency of zone files, out of sync MX

Hello, What do you guys recommend to audit every resource record in a zone file against all the records in all the DNS. I want something that I feed the master zone file and then goes to each NS server and ensures that the records are correct in all of them. For some strange reason all my DNS servers have the same SOA Serial, but after deleting two MX records, some 4 out of 5 the DNS servers have not taken this update. I've yet to figure out the cause, but I see that SOA Serial is not to be trusted. Regards, Maren.