Announcements
11/06/2026
DELIVERY - Westpac Area – Arizona – New Mexico District Blue Post Office – Resume Operations
Announcements
11/06/2026
PROCESSING AND DISTRIBUTION - Update - Des Moines, IA Processing and Distribution Center (P&DC) Reopened
Announcements
11/06/2026
DELIVERY - Southern Area -Tennessee District - Copperhill Post Office (37317) Temporarily Suspended
Announcements
11/06/2026
INFORMATIONAL - PostalOne! Alert – November 15, 2026
Announcements
11/06/2026
INFORMATIONAL - Commercial System Releases – Week of November 14, 2026
Release Notes
11/06/2026
November 15 2026 USPS Ship 31.0.0.0 Release Notes
Release Notes
11/06/2026
November 15 2026 PostalOne! 64.1.3.0 Release Notes
Announcements
11/05/2026
DELIVERY - Central Area - Vining IA Post Office (52348) - Temporarily Suspending Operations
Announcements
11/05/2026
DELIVERY - Central Area - Compton IL RMPO 61318 - Closed Indefinitely 11.05.2026
Announcements
11/05/2026
PROCESSING AND DISTRIBUTION - Possible Delays – Des Moines, IA Processing and Distribution Center (P&DC)
Announcements
11/05/2026
PROCESSING AND DISTRIBUTION - Billings, MT Processing and Distribution Center (P&DC) Machine Upgrade
Error Codes
11/05/2026
Known Issues List 11.3.2026
Contact Lists
11/05/2026
CASS™ Certified Products Guide: Residential Delivery Indicator Cycle O - (Expires July 31, 2028)
Contact Lists
11/05/2026
RDI™ Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)

This document outlines the CASS/MASS certified vendors list for RDI™ Cycle O.

Contact Lists
11/05/2026
CASS™ Certified Products Guide: M L O C R Mailers/Users Data File Cycle O - (Expires July 31, 2028)
Contact Lists
11/05/2026
CASS™ Certified Products Guide: M L O C R Mailers/Users Cycle O - (Expires July 31, 2028)
Contact Lists
11/05/2026
CASS™ Certified Products Guide: M L O C R Service Bureaus Data File Cycle O - (Expires July 31, 2028)
Contact Lists
11/05/2026
CASS™ Certified Products Guide: M L O C R Service Bureaus Cycle O - (Expires July 31, 2028)
Contact Lists
11/05/2026
CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Data File Cycle O - (Expires July 31, 2028)
Contact Lists
11/05/2026
CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Cycle O - (Expires July 31, 2028)
Contact Lists
11/05/2026
CASS™ Certified Products Guide: Z4CHANGE Data File Cycle O - (Expires July 31, 2028)
Contact Lists
11/05/2026
CASS™ Certified Products Guide: Z4CHANGE Cycle O - (Expires July 31, 2028)
Contact Lists
11/05/2026
CASS™ Certified Products Guide: Vendor/Service Licensees Data File Cycle O - (Expires July 31, 2028)
Contact Lists
11/05/2026
CASS™ Certified Products Guide: Vendor/Service Bureaus Licensees Cycle O - (Expires July 31, 2028)
Contact Lists
11/05/2026
CASS™ Certified Products Guide: DSF2® Licensees Data File Cycle O - (Expires July 31, 2028)