The online manual website indicates that "The provisions of the current Manual remain effective until modified by the 30th General Assembly, scheduled to convene in June of 2023, and a new version is announced by the Board of General Superintendents."
Church of the Nazarene Manual 2017–2021, Dean G. Blevins, Stanley J. Rodes, Terry S. Sowden, James W. Spear, David P. Wilson (eds.), Kansas City, MO: Nazarene Publishing House (2017): para. 31.