Message on USNBT market says:
USNBT / BTC market is closing
Due to the recent network fork of USNBT and outright rude community we have decided to delist. please close all open orders and withdraw before 27/09/2017
Eight days ago when I noticed they had upgraded was September 12, leaving only half the announced time if they do close down USNBT entirely that date. I have to agree that’s worrying.