Contact Lists
06/26/2025
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.

User Guides
06/26/2025
Mailing and Shipping Solutions Center (MSSC) Topics

List of topics the MSSC can assist with. To reach the MSSC, email us at MSSC@usps.gov or call 1-877-672-0007 from 7:00AM – 7:00PM CT.

Fact Sheets
06/26/2025
About Mailers' Technical Advisory Committee (MTAC) User Group 4

This document provides a brief description of MTAC User Group 4 for mail visibility and provides a contact for requesting to join the group.

Data Files
06/26/2025
Z4 Info File

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

Data Files
06/26/2025
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.

 

Announcements
06/25/2025
INFORMATIONAL - Key Personnel Announcements in the Chief Technology and Engineering Group
Announcements
06/25/2025
INFORMATIONAL - Executive Retirement - Scott R. Bombaugh Chief Technology Officer & Executive Vice President
Announcements
06/25/2025
INFORMATIONAL - Priority Mail Open and Distribute (PMOD) Service Updates
Announcements
06/25/2025
DELIVERY - Southern Area – Alabama-Mississippi District - Rolling Fork Post Office (39159) – Resumed Operations
Data Files
06/25/2025
Informed Visibility® Mail Tracking & Reporting (IV®-MTR) Operation Codes List

This spreadsheet provides a list of operation codes (opcodes), also known as Scan Event Codes, for the IV-MTR application.