Cal. Bus. & Prof. Code § 2984
Except as provided in Section 2985, a license that has expired may be renewed at any time within three years after its expiration on filing of an application for renewal on a form prescribed by the board and payment of all accrued and unpaid renewal fees. If the license is renewed after its expiration, the licensee, as a condition precedent to renewal, shall also pay the prescribed delinquency fee, if any. Renewal under this section shall be effective on the date on which the application is filed, on the date on which all renewal fees are paid, or on the date on which the delinquency fee, if any, is paid, whichever last occurs. If so renewed, the license shall continue in effect through the expiration date provided in Section 2982 which next occurs after the effective date of the renewal, when it shall expire and become invalid if it is not again renewed.
Ca. Bus. and Prof'l. Code § 2984