With the old WebGUI, I was able to setup dyndns without problems (screenshot is configured and functional). On the new WebGUI, just looking at the WebGUI is a clear indication of problems. The two attached screenshots are from the same system, just with the different WebGUIs. The issues namely are:
1. The provider field is now waiting for input. It's already in the config file (dyndns).
2. I have no idea what these "default@" things are when you click on the dropdown for provider. As far as I'm concerned, that field is nonsensical and only adds confusion to the user. Is "default" a username?
3. dyndns (and others) have their own checkip server and checkip path. The old WebGUI note says "The client IP is detected by calling 'url' from this 'ip_server_name:port /.'. Leaving this field blank causes the service to use its built in default: checkip.dyndns.org:80 /." and the new UI not only doesn't say that, it requires me to put something in the field. To make matters worse, dyndns documentation makes no mention of a checkip server, because they do internally and automatically.
4. I cannot save changes without breaking the service that is already working because of #3.