Contact Lists
07/31/2025
CASS™ Certified Products Guide: DSF2® Licensees Data File Cycle O - (Expires July 31, 2028)
Contact Lists
07/31/2025
DSF2® Licensees Cycle O: Certified Products Guide - (Expires July 31, 2028)
Contact Lists
07/31/2025
DPV® Licensees Data File Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)
Contact Lists
07/31/2025
DPV® Licensees Cycle O: Certified Products Guide - (Expires July 31, 2028)
Contact Lists
07/31/2025
CASS™ Software Manufacturers Data File Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)
Contact Lists
07/31/2025
CASS™ Software Manufacturers Cycle O - (Expires July 31, 2028)
Contact Lists
07/31/2025
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
07/31/2025
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.

Error Codes
07/31/2025
Mail Quality Data through IV-MTR Error Codes

The attached is a listing of error codes. It identifies which codes are currently available in MQD-IV provisioning and also whether the error codes are also available in the drills from the Mailer Scorecard.

Data Files
07/31/2025
Z4 Info File

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