New version is here (earlier than I thought), and probably this is the end of the toilet and sewer content
100 more years of toilet/sewer content, actually.
There's 5 areas that have enemies using a toilet which are presumably boss fights. This update adds fights for two of them (one urine focused one fart focused) so there's still 3 more to go. In addition, there's a new save area at the end of a very long clogged tunnel which has an exit that doesn't have a warp associated with it yet so there's probably more stuff intended to be added.
That said, I expect the author will finish the three boss fights here and then go do something else, because that tends to be their style.