Section 20. (a) Except as provided in section 21, all meetings of a public body shall be open to the public.

(b) Except in an emergency, in addition to any notice otherwise required by law, a public body shall post notice of every meeting at least 48 hours prior to the meeting, excluding Saturdays, Sundays and legal holidays. In an emergency, a public body shall post notice as soon as reasonably possible prior to the meeting. Notice shall be printed in a legible, easily understandable format and shall contain the date, time and place of the meeting and a listing of topics that the chair reasonably anticipates will be discussed at the meeting.

(c) For meetings of a local public body, notice shall be filed with the municipal clerk and posted in a manner conspicuously visible to the public at all hours in or on the municipal building in which the clerk's office is located.

For meetings of a regional or district public body, notice shall be filed and posted in each city or town within the region or district in the manner prescribed for local public bodies. For meetings of a regional school district, the secretary of the regional school district committee shall be considered to be its clerk and shall file notice with the clerk of each city or town within the district and shall post the notice in the manner prescribed for local public bodies. For meetings of a county public body, notice shall be filed in the office of the county commissioners and a copy of the notice shall be publicly posted in a manner conspicuously visible to the public at all hours in the places as the county commissioners shall designate for the purpose.

For meetings of a state public body, notice shall be filed with the attorney general by posting on a website under the procedures established for this purpose and a duplicate copy of the notice shall be filed with the regulations division in the state secretary's office.

The attorney general may prescribe or approve alternative methods of notice where the attorney general determines the alternative methods will afford more effective notice to the public.

(d) The attorney general may, by regulation or letter ruling, authorize remote participation by members of a public body not present at the meeting location; provided, however, that the absent members and all persons present at the meeting location are clearly audible to each other; and provided further, that a quorum of the body, including the chair, are present at the meeting location. The authorized members may vote and shall not be deemed absent for the purposes of section 23D of chapter 39.

(e) A local commission on disability may by majority vote of the commissioners at a regular meeting authorize remote participation applicable to a specific meeting or generally to all of the commission's meetings. If a local commission on disability is authorized to utilize remote participation, a physical quorum of that commission's members shall not be required to be present at the meeting location; provided, however, that the chair or, in the chair's absence, the person authorized to chair the meeting, shall be physically present at the meeting location. The commission shall comply with all other requirements of law.

(f) After notifying the chair of the public body, any person may make a video or audio recording of an open session of a meeting of a public body, or may transmit the meeting through any medium, subject to reasonable requirements of the chair as to the number, placement and operation of equipment used so as not to interfere with the conduct of the meeting. At the beginning of the meeting, the chair shall inform other attendees of any recordings.

(g) No person shall address a meeting of a public body without permission of the chair, and all persons shall, at the request of the chair, be silent. No person shall disrupt the proceedings of a meeting of a public body. If, after clear warning from the chair, a person continues to disrupt the proceedings, the chair may order the person to withdraw from the meeting and if the person does not withdraw, the chair may authorize a constable or other officer to remove the person from the meeting.

(h) Within 2 weeks of qualification for office, all persons serving on a public body shall certify, on a form prescribed by the attorney general, the receipt of a copy of the open meeting law, regulations promulgated under section 25 and a copy of the educational materials prepared by the attorney general explaining the open meeting law and its application under section 19. Unless otherwise directed or approved by the attorney general, the appointing authority, city or town clerk or the executive director or other appropriate administrator of a state or regional body, or their designees, shall obtain certification from each person upon entering service and shall retain it subject to the applicable records retention schedule where the body maintains its official records. The certification shall be evidence that the member of a public body has read and understands the requirements of the open meeting law and the consequences of violating it.