YS> 2nd is the SOA serial number. the report say, as per RFC1912 2.2 that
YS> i must have the date as part of the number.

RFC 1912 doesn't say that one _must_ use that format. It recommends it.
But like several of the recommendations in RFC 1912, it's myopic at
best. Use the date if you are maintaining the serial number by hand.
If, however, you are using one of the several modern DNS server
softwares that maintain the serial number for you, such as Microsoft's
DNS server in Windows NT 2000 Server and later when using Active
Directory Integrated "zones", ignore the recommendation.