The Postal ServiceTM is revising Mailing Standards of the United States Postal Service, Domestic Mail Manual (DMM®) to require Detached Mail Unit (DMU) mailers and mailers that enter full-service mailings at a Business Mail Entry Unit (BMEU) to participate in Seamless Parallel by June 1, 2020. In addition, the Postal Service provides advance notice of its intent: To require all mailers with an authorized Detached Mail Unit to enroll in the Seamless Acceptance Program by May 1, 2021; and to verify all BMEU-entered full-service mailings using only automated sampling and verification processes beginning July 1, 2021.