CASS™ Software Manufacturers Data File Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)

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.

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.

INFORMATIONAL: 2026 National Postal Forum - New NPF Vignettes Track

INFORMATIONAL - Kansas City Processing and Distribution Center New Package Sorting Equipment Installation

DELIVERY - International Service Suspension Notice March 20, 2026 - Lebanon

USPS API MCAT - TechSheet

Coming soon..

USPS SHIP MCAT - TechSheet

Coming soon..

Mail.xml Technical Specifications R64.0.0.0

Mail.dat Technical Specifications R64.0.0.0

Enterprise Payment System (EPS) User Guide

PCC National Monthly Touchpoint (March)

PCC National Monthly Touchpoint (March) Zoom Recording

Passcode: W?PwtL0?

INFORMATIONAL - Central Area AIM Meeting 2026 SAVE-THE-DATE - JUNE 30th 2026

INFORMATIONAL - Major Storm Impacting Shipping Services in Eastern and Central Regions

PTR2 Release Notes_DD_03_12_26

Adjustments to Mail Growth Incentives Registration

MGI Customers can submit multiple requests to the Program Office to initiate discussions for adjusting existing Incentives Registration service requests that are in review.

Mail Growth Incentives New Registration User Guide

On September 27, 2023, the Postal Regulatory Commission (PRC) approved the request by the United States Postal Service (UPSP) to update the Mail Classification Schedule (MCS) by establishing two separate Mail Growth Incentives (MGI): the First-Class Mail Growth Incentive and the Marketing Mail Growth Incentive. These incentives will run simultaneously from January 1 through December 31.

INFORMATIONAL - New Portal to Premium Forwarding Service Commercial (PFSC)

Known Issues List 3.12.2026

Mail Growth Incentives FAQs

The FAQ page will be back soon. Sorry for the inconvenience. 

***Updated - New Areas*** - Area District 5-digit ZIP Codes (AREADIST_ZIP5.TXT)

City/State ZIP Code Weekly Compare

3 Digit ZIP/AISU Office List (AISUREPT.TXT)