I've added a new section to the ddns config on my router (running Openwrt) to update the ip address through an opendns server. I had to install curl, the opendns server returns a "badauth" if you don't use curl. It seems to work now. I'll check again...

I don't understand the decision to kill dns-o-matic. The best way to keep opendns up to date with the ip address is through a device that's always on when you're using opendns and that's the router. There are days that I don't use my laptop but still...