County boards of education may renew any certificate legally issued by them prior to October 1, 1945, and now in force; provided, that no certificate granted upon a credential issued by the State Board of Education or commission for a limited period shall be renewed or extended unless the credential upon which it was issued has been renewed or extended, and then only for the period of the renewal or extension of the credential.
(Enacted by Stats. 1976, Ch. 1010.)