Also see:
http://www.cnn.com/2017/09/25/politics/travel-ban-3-0-could-derail-supreme-court-case/index.html
“In general, when one policy expires and a new policy is developed, the court may consider any challenge to the expired policy to be moot,” said Irv Gornstein, the executive director of the Supreme Court Institute at Georgetown Law. Gornstein stressed he was talking generally, but he suggested that if the parties are no longer affected by the new policy, or its impact has changed, there may not be the injury that is necessary to establish a case — potentially meaning things will have to start anew. “