setting ip-address into the URL with dietpi-ddns for DynDNS2-protocol

I’m trying to set up dyndns with dietpi-ddns.
My provider https://www.inwx.de claims to use the DynDNS2-protocol and wants a URL in the following format: https://dyndns.inwx.com/nic/update?myip=&myipv6=
The ip6 address is optional.
How can I get dietpi-ddns to put my current public DNS-address into the URL?

Thanks in advance.

Hi,

I guess you would need to wrap this into a script, to check the IPv6 address first. An idea could be following https://gist.github.com/cyrusboadway/5a7b715665f33c237996