must be served upon the opposing party at the time of filing. The appellee's brief must be served and filed no later than 21 days after service of the appellant's brief.
N.D. R. App. P. 2.2
Joint Procedure Committee Minutes of April 26, 2019, page 19; September 26, 2013, pages 13-14; April 29-30, 2010, page 20; April 24-25, 2008, pages 9-11.