Multiple outlets, including Alan Arnette and Stefan Nestler, are reporting that the expedition has been postponed because two of the clients were forced to withdraw. Originally, the winter Everest attempt was set to begin on December 1 and run through February 28, which means the teams would have arrived in Base Camp and had a chance to start their acclimatization prior to the start of the winter season. That schedule would have also afforded them plenty of time to reach the summit –– if that were even possible considering the weather conditions –– before the end of winter arrived in March.
Throughout the history of climbing on Everest, only about 15 successful summits have been recorded in winter, with the most recent of those occurring some 25 years ago. That doesn't necessarily bode well for a commercial expedition, but Seven Summit Treks is determined to give this expedition a go in 2019-2020. The SST team gained a lot of valuable experience supporting Txikon on Everest these past two winters, and although he was unsuccessful in his attempt to climb the world's highest peak without oxygen, they seem to see the potential for a small, but profitable, market for winter mountaineering.
Will this venture ultimately be a successful one? We'll just have to wait until next year to find out.