PowerDNS OpenDBX Backend/Configuration/Auto serials
Since version 2.9.22, the PowerDNS OpenDBX backend supports the automatic calculation of SOA serials. The serial field in the SOA record can be represented by a number which is incremented each time a new record is inserted, an existing record is updated or an old record is deleted inside the zone. This behavior is supported by all OpenDBX database backends which provide triggers (currently, all databases supported by the PowerDNS OpenDBX backend do this).
To enable this feature you have to set the serial number in the SOA record of the zone to zero ("0"), e.g.
ns.example.com. hostmaster.example.com. 0 86400 900 604800 3600
The serial number is the third field respectively the first numeric value in the SOA record. This causes the PowerDNS OpenDBX backend to use the column "auto_serial" in the "domains" table of the associated zone instead of the value in the SOA record. Please be sure that you've updated the database schema to the latest version.
Using the automatic serial calculation can be enabled on a per zone basis. For already existing zone with given serials you can add the current value of the SOA serial to the value of the "auto_serial" column to provide consecutive serial numbers. Alternatively, PowerDNS also provides the possibility to add a certain value to all SOA serials on the fly via the "soa-serial-offset" parameter.