Vt. Stat. Ann. tit. 8, § 4226

When notice required under section 4224 or 4225 of this title is provided by mail, such notice shall be by certified mail, except that in the case of cancellation for nonpayment of premium, notice shall be by certified mail, certificate of mailing, or any similar first-class mail tracking method used or approved by the U.S. Postal Service, including Intelligent Mail barcode Tracing (IMb Tracing). A certificate of mailing from the U.S. Postal Service does not include a certificate of bulk mailing.