Contact Lists
06/25/2026
CASS™ Software Manufacturers Cycle O - (Expires July 31, 2028)
Contact Lists
06/25/2026
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.

Data Files
06/25/2026
Z4 Info File

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

Data Files
06/25/2026
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.

 

Announcements
06/24/2026
INFORMATIONAL - Enterprise Payment System (EPS) – INCIDENT #10784524 Processing Postage Statement Error
Publications
06/24/2026
MGI Credit Claim Request Deck
Data Files
06/24/2026
Updated List: Service Type Codes for Intelligent Mail® Package Barcode (IMpb)

This document provides the updated service type codes for  Intelligent Mail® Package Barcodes.

Announcements
06/23/2026
INFORMATIONAL - Domestic HAZMAT Handling and Noncompliance Fees
Announcements
06/23/2026
DELIVERY - WestPac Area - California 1 District - Santa Rosa Annex Post Office (95407) - Relocation
Presentations
06/23/2026
Pop-Up Mini-Cafe: Site Synergy: WestPac PCCs Lead the Way Mini Café