Contact Lists
04/02/2026
CASS™ Software Manufacturers Data File Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)
Contact Lists
04/02/2026
CASS™ Software Manufacturers Cycle O - (Expires July 31, 2028)
Contact Lists
04/02/2026
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
04/02/2026
Z4 Info File

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

Data Files
04/02/2026
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
04/01/2026
INFORMATIONAL - USPS Modernization Through Package Equipment Upgrades in April 2026
Announcements
04/01/2026
INFORMATIONAL - Atlantic Area AIM Meeting June 2, 2026
Data Files
04/01/2026
March 2026 Nixie Volume

This spreadsheet contains the UAA statistics for March 2026.

Announcements
04/01/2026
INFORMATIONAL - Federal Register - Manifest Mailing System Retired April 1, 2026
Data Files
04/01/2026
Informed Visibility Mail Tracking & Reporting Machine Count

List of US Postal Service machines by site, including a description of each machine.