03/03/2026
Ancillary Service Endorsement Fact Sheet
Ancillary service endorsements are used by mailers to request an addressee’s new address or the reason mail cannot be
delivered as addressed and to provide the US Postal Service with instructions on how to handle Undeliverable As Addressed
(UAA) mailpieces.
02/12/2026
Manifest Mailing Systems Retirement Fact Sheet
The USPS is amending Mailing Standards of the United States Postal Service, Domestic Mail Manual (DMM) subsection 703.2.0 to retire the manifest mailing system (MMS). Effective April 1, 2026.
12/18/2025
Addressing Fact Sheet for First-Class Flats
This document is for mailers who are sending flat-size mail (such as large envelopes) at Automation and Presorted First-Class Mail prices. To use these prices, you must mail at least 500 pieces at a time, prepared and sorted according to Postal Service guidelines.
12/16/2025
Addressing Fact Sheet for USPS Marketing Mail Flats
This document is for business mailers who are sending flat-size USPS Marketing Mail (such as large envelopes, catalogs, and circulars). To use the USPS Marketing Mail prices, you must send at least 200 pieces or 50 pounds of mail at a time, prepared and sorted according to Postal Service guidelines.
11/12/2025
USPS Ship Package Data Feeds
This document outlines the steps for shippers to access package data feeds through the USPS Informed Visibility Mail Tracking & Reporting (IV-MTR) application.