Custom Dynamic DNS
How to configure a Custom Dynamic DNS?
Due to how I use my domain at namecheap, and a bug in the built in updater, I couldn't use the built in one.
What would probably work in your case would be installing the Cron package and then setting up a cronjob to do the work
/usr/bin/nice -n20 fetch -o /dev/null "https://dynamicdns.park-your-domain.com/update?host=@&domain=sub.domain.ext&password=passwordhere"
Which I have set to run at 12:10 am and 12:10 pm.