(2) Initial notice of a contested case or arbitration directed by the board to the last-known address of record for a landscape construction professional or landscape contracting business is considered delivered to the professional or business when deposited in the United States mail and sent registered, certified or post office receipt secured. Any other communication directed by the board to the last-known address of record for a landscape construction professional or landscape contracting business is considered delivered to the professional or business when deposited in the United States mail, regular mail. [2001 c.409 §14; 2005 c.609 §13; 2007 c.541 §25; 2015 c.672 §10]