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.

Last Mile Bidding Process Webinar

Shippers who wish to access the DDU network will have the ability to propose a combination of volume, pricing and tender times at each location, with deliveries for successful bidders being made by USPS that same day or the next day, at the customer’s preference. 

Tracking Access Control Tech Sheet

Package Tracking allows seamless integration of real-time tracking information into business systems, enabling monitoring of USPS package status from shipment to delivery.  USPS is upgrading tracking data access to enhance security and combat fraud by modernizing and securing customer access.

July 2026 Release Overview

Note: For the latest technical specifications, please see the July 2026 Price Change Release Notes as they are published.

Quick Reference Guide: Bundle Preparation and Handling Recommendations

A guide to ensuring your bundles stay secure during transit.

Viewing MGI Credit Balances and Postage Statements

Properly Securing Bundles of Flats

Please note that as of July of 2025, the Postal Service no longer permits using rubber bands and twine or string for securing bundles of flats, with the exception of bundles of First-Class Mail® flats placed in flat trays.

Package Tracking Options and Modernization

Explore package tracking options with our Product Tracking and Reporting (PTR) application and learn about the planned changes in our recent platform modernization efforts.

Catalog Insights Promotion FAQ

FAST-Initial Signup and Appointment Scheduling

This covers USPS facility appointments for package induction changes and a detailed walkthrough of how to create and manage appointments and access reports within the Facilities Access and Shipment Tracking (FAST) application.

Publication for Streamlined Mail Acceptance for Letters and Flats (Pub 685)

Streamlined Mail Acceptance for Letters and Flats (Pub 685) contains the policies and processes for the verification of eligible business mailings using tools provided by Intelligent Mail® Full-Service, eInduction, and Seamless Acceptance.

INFORMATIONAL: Mercury Remains Prohibited in The Mail

First-Class Mail and Marketing Mail Growth Incentives FAQs

On September 27, 2023, the Postal Regulatory Commission (PRC) approved the Postal Service request to make Mail Classification Schedule (MCS) changes to establish two distinct Mail growth incentives — a First Class Mail Growth Incentive and a Marketing Mail Growth Incentive.

CASS™ Software Manufacturers Cycle O - (Expires July 31, 2028)

CASS™/MASS™ Certified Products Guide - All Sections Data Files Cycle O - (Expires July 31, 2028)

This document contains the certified vendors list for CASS™ and MASS™ products for Cycle O.

Intelligent Mail Matrix Barcode (IMmb) Technical Specifications

Shipping labels on irregularly-shaped packages, softpacks, and polybags can easily become distorted or creased during automated parcel processing making reading the traditional, linear IMpb barcode challenging to scan.  USPS has developed the IMmb to help overcome these challenges and improve package visibility.  IMmb barcodes contain the same data as is in the IMpb barcode; however, they use a more robust, space-efficient robust barcode symbology for encodation.  The smaller barcode footprint allows two IMmb barcodes to be added within unused areas of existing standard shipping labels.  The result is redundancy of the barcode data giving sorters two additional chances to read the barcode. 

Z4 Info File

A downloadable ZIP file containing information related to the Z4 Info File

Early Warning System (EWS002C0.ZIP)

This file is the EWS production file and is updated weekly. This file contains the Early Warning System data file for the CASS™ and MASS™ certification process.