A vacancy occurring in the board of directors and a directorship to be filled by reason of an increase in the number of directors may be filled by the affirmative vote of a majority of the remaining directors, though less than a quorum of the board of directors, unless the articles of incorporation or the bylaws provide that a vacancy or directorship so created shall be filled in some other manner. A director elected or appointed to fill a vacancy shall be elected or appointed for the unexpired term of the director’s predecessor in office. A directorship to be filled by reason of an increase in the number of directors shall be filled by the board of directors for a term of office which continues only until the next election of directors. In no case may a vacancy continue for longer than six months or until the next annual meeting of the members, whichever occurs first.