I am from Malaysia and using cable service.
In my previos router (Asus, TP-Link and Linksys), I used to configure their DDNS feature page to access DNS-O-Matic to update OpenDNS (for parental control) and FreeDNS (for DDNS service).
If I go to http://updates.dnsomatic.com/nic/update? manually and supply with my credential, I can see that DNS-O-Matic will update OpenDNS and FreeDNS with my current IP address.
I think maybe the FW did not code to work with DNS-O-Matic API (https://www.dnsomatic.com/wiki/api).
At some point, I actually give up and want to try use DDNS service from dlinlddns.com, it during registration it keep saying my serial number is invalid.