Release Notes
10/24/2026
Informed Delivery API Release Notes V1.0.3
Technical Specifications
10/24/2026
Informed Delivery API Technical Specifications V1.0_5.1
Announcements
10/23/2026
INFORMATIONAL - Informed Delivery Mailer Campaign Portal (MCP) Scheduled Outage on October 24
Announcements
10/23/2026
INFORMATIONAL - Postal One System Promotions Not Applied to Postal Wizard Statements
Release Notes
10/23/2026
October 23, 2026 Program Registration 31.4.0.0 Pre-Release Notes

Coming soon.

Contact Lists
10/23/2026
Mailers Technical Advisory Committee (MTAC) Membership Roster and Vacancies
Program Requirements
10/23/2026
Plus One Product Requirements (Technical) (Updated 10/23/26)

Plus One Updated 10/23/26

Contact Lists
10/22/2026
CASS™ Certified Products Guide: Residential Delivery Indicator Cycle O - (Expires July 31, 2028)
Contact Lists
10/22/2026
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
10/22/2026
CASS™ Certified Products Guide: M L O C R Mailers/Users Data File Cycle O - (Expires July 31, 2028)