Data Files
09/01/2026
August 2026 Nixie Volume

This spreadsheet contains the UAA statistics for August 2026.

Error Codes
09/01/2026
Contact Lists
09/01/2026
MPE (Mail Processing Equipment) Service Provider Licensees

Marketing contact information for certified Mail Processing Equipment (MPE) licensees 

Publications
08/31/2026
Data Files
08/31/2026
Contact Lists
08/31/2026
Mail Service Provider (MSP) - Full-Service Certified Mailers

A Mail Service Provider (MSP) offers a variety of solutions to prepare and present Full-Service presort mailings. For more information regarding Certified MSPs, please follow this link: https://postalpro.usps.com/full-service-cert/fact-sheet

 

Data Files
08/31/2026
Data Files
08/31/2026
Move to Competitive Street Addressing (MTC SA) List

This .txt file contains the MTC SA List.

Release Notes
08/28/2026
USPS APIs Release Notes

For the latest updates, please review the USPS APIs Release Notes.

Release Notes
08/27/2026
Data Files
08/27/2026
Informed Visibility® Mail Tracking & Reporting (IV®-MTR) Development Tracker

This document provides a list of active IV-MTR work to be as well as items completed in the current fiscal year.

 

*Please note, Postal Pro is the only source for a current IV-MTR Development log as updates will be made on an ongoing basis.

Contact Lists
08/27/2026
RDI™ Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)

This document outlines the CASS/MASS certified vendors list for RDI™ Cycle O.

Contact Lists
08/27/2026
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.

Release Notes
08/27/2026
Informed Visibility® Mail Tracking & Reporting (IV®-MTR) Release Notes

These release notes summarize new features and enhancements implemented in deployments to the IV-MTR application.

Data Files
08/27/2026
Z4 Info File

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

Data Files
08/27/2026
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.