Every general rule, regulation or order of the board shall be posted for public inspection in the main office of the board at least six days before it shall become effective, where it shall remain conspicuously posted until twenty days after its effective date, and shall be given such further publicity, by advertisement or announcement, in a newspaper or otherwise, as the board shall deem advisable. At least three days before it shall become effective, copies of such general rule, regulation or order shall be mailed to all licensees and producers' groups and organizations affected thereby: Provided, however, That such mailing shall not be construed as a condition upon which the validity of any such rule, regulation or order depends. A certified copy of an order applying only to the particular person or persons named therein shall be served on the person or persons affected.

An order, herein required to be served, shall be (1) served in the manner now or hereafter established by law for the service of writs of summons, except that such service need not be made by the sheriff; or (2) mailed, registered and charges prepaid, (a) in the case of an individual, to his last known residence or place of business, (b) in the case of an unincorporated association or a corporation formed under the laws of this Commonwealth, to its principal office, and (c) in the case of a corporation formed under the laws of any other state, to the office of its duly authorized agent in Pennsylvania, or, if there be no duly authorized agent in Pennsylvania, to its home office in the state of incorporation or in any other state.

The posting in the main office of the board of any rule, regulation or order not herein required to be served, and the giving of such further publicity thereto as the board deems advisable, or the proper service of any rule, regulation or order required to be served, shall constitute due and sufficient notice to all persons affected by such rule, regulation or order. A rule, regulation or order of the board when duly posted and so publicized, or when properly served, as provided in this section, shall have the force and effect of law. The board shall, upon request, mail to any person a copy of any general rule, regulation or order of the board.

The mailing, or service by mail, herein required, shall be by deposit in a United States Post Office, or in any receptacle thereof. Service by registered mail as provided in this section shall be effective notwithstanding the refusal of the addressee to accept or receive an order so served.