Regulations, restrictions, and boundaries authorized to be created pursuant to sections 19-901 to 19-915 may from time to time be amended, supplemented, changed, modified, or repealed. In case of a protest against such change, signed by the owners of twenty percent or more either of the area of the lots included in such proposed change, or of those immediately adjacent on the sides and in the rear thereof extending three hundred feet therefrom, and of those directly opposite thereto extending three hundred feet from the street frontage of such opposite lots, and such change is not in accordance with the comprehensive development plan, such amendment shall not become effective except by the favorable vote of three-fourths of all the members of the city council or village board of trustees of such municipality. The provisions of section 19-904 relative to public hearings and official notice shall apply equally to all changes or amendments. In addition to the publication of the notice as provided in section 19-904, a notice shall be posted in a conspicuous place on or near the property on which action is pending. Such notice shall not be less than eighteen inches in height and twenty-four inches in width with a white or yellow background and black letters not less than one and one-half inches in height. Such posted notice shall be so placed upon such premises that it is easily visible from the street nearest the same and shall be so posted at least ten days prior to the date of such hearing. It shall be unlawful for anyone to remove, mutilate, destroy, or change such posted notice prior to such hearing. Any person so doing shall be deemed guilty of a misdemeanor punishable as provided in section 19-913. If the record title owners of any lots included in such proposed change be nonresidents of the municipality, then a written notice of such hearing shall be mailed by certified mail to them addressed to their last-known addresses at least ten days prior to such hearing. At the option of the city council or village board of trustees of the municipality, in place of the posted notice provided in this section, the owners or occupants of the real estate to be zoned or rezoned and all real estate located within three hundred feet of the real estate to be zoned or rezoned may be personally served with a written notice thereof at least ten days prior to the date of the hearing, if they can be served with such notice within the county where such real estate is located. When such notice cannot be served personally upon such owners or occupants in the county where such real estate is located, a written notice of such hearing shall be mailed to such owners or occupants addressed to their last-known addresses at least ten days prior to such hearing. The provisions of this section in reference to notice shall not apply (1) in the event of a proposed change in such regulations, restrictions, or boundaries throughout the entire area of an existing zoning district or of such municipality, or (2) in the event additional or different types of zoning districts are proposed, whether or not such additional or different districts are made applicable to areas, or parts of areas, already within a zoning district of the municipality, but only the requirements of section 19-904 shall be applicable.