California CodesCode of Civil Procedure - CCPPreliminary ProvisionsSection 11
Wherever any notice or other communication is required by this code to be mailed by registered mail by or to any person or corporation, the mailing of such notice or other communication by certified mail shall be deemed to be a sufficient compliance with the requirements of law.
Notes
Allows certified mail to satisfy any Code requirement that a notice or other communication be mailed by registered mail, whether the mailing is by or to a person or corporation. The substitution is deemed sufficient compliance with the legal registered-mail requirement and states no additional deadline, proof requirement, monetary condition, or exception.
Use as reference
Lexinter.net | California Code, Code of Civil Procedure - CCP § 11 | https://laws.lexinter.net/codes/california/code-of-civil-procedure/preliminary-provisions/section-11