Conn. Gen. Stat. § 49-6c

A creditor shall mail to a consumer debtor a written notice of the imposition of any delinquency charge, late fee or similar assessment as a result of a late payment on a note, mortgage or installment sales contract unless the creditor issues a periodic statement which may include any delinquency charge, late fee, or similar assessment. Such notice shall be mailed within sixty days of the imposition of such charge.