California Code, Elections Code - ELEC § 2106

A program adopted by a county pursuant to Section 2103 or 2105, that is designed to encourage the registration of electors, shall contain the following statement in printed literature or media announcements made in connection with the program: “A person entitled to register to vote must be a United States citizen, a resident of California, not currently imprisoned in a state or federal prison for the conviction of a felony, and at least 18 years of age at the time of the election. A person may preregister to vote if that person is a United States citizen, a resident of California, not currently imprisoned in a state or federal prison for the conviction of a felony, and at least 16 years of age.” A county elections official may continue to use existing materials before printing new or revised materials required by any changes to this section.