Contact Lists
01/15/2026
DPV® Licensees Cycle O: Certified Products Guide - (Expires July 31, 2028)
Contact Lists
01/15/2026
CASS™ Software Manufacturers Data File Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)
Contact Lists
01/15/2026
CASS™ Software Manufacturers Cycle O - (Expires July 31, 2028)
Contact Lists
01/15/2026
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
01/15/2026
Z4 Info File

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

Data Files
01/15/2026
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
01/14/2026
INFORMATIONAL - USPS APIs System Maintenance January 28, 2026
Release Notes
01/14/2026
USPS APIs Release Notes

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

Announcements
01/13/2026
INFORMATIONAL - Extended Customer Webinars on Upcoming USPS Tracking Data Access Controls
Announcements
01/13/2026
INFORMATIONAL - July Price Change 2026 -Release Overview