Cal. Bus. & Prof. Code § 124

Notwithstanding subdivision (c) of Section 11505 of the Government Code, whenever written notice, including a notice, order, or document served pursuant to Chapter 3.5 (commencing with Section 11340), Chapter 4 (commencing with Section 11370), or Chapter 5 (commencing with Section 11500), of Part 1 of Division 3 of Title 2 of the Government Code, is required to be given by any board in the department, the notice may be given by regular mail addressed to the last known address of the licentiate or by personal service, at the option of the board.