Neb. Rev. Stat. § 1-141: Neb. Rev. Stat. § 1-141

A written notice stating the nature of the charge or charges against the accused and the time and place of the hearing before the board on such charges shall be served on the accused not less than thirty days prior to the date of said hearing either personally or by mailing a copy thereof by either registered or certified mail to the address of the accused last known to the board.