Many HN clients are dead or abandoned; I'll circle back in a year.
I also plan to add support for comment and post submissions. I hope I'll have the time to do so in the next few weeks.
Most of the HN apps still work even if abandoned -- it's the UI framework demo websites (HN UX re-skin seems to be right after the TODO app demo) that have all disappeared. Also the audio ones, but there haven't been many of those.