Announcements
06/28/2025
INFORMATIONAL: USPS APIs System Maintenance - June 30, 2025
Announcements
06/28/2025
DELIVERY: Atlantic Area - Maryland District - Oxford Post Office (21654) - Temporarily Closed
Announcements
06/27/2025
DELIVERY - Central Area – Ohio 1 District - Rogers Post Office - 44455
Announcements
06/27/2025
INFORMATIONAL - The MSSC Announces EVS Email Addresses Decommissioned
Publications
06/27/2025
Labeling List Changes Effective August 1, 2025

Effective August 1, 2025, the Postal Service™ will revise Labeling List(s) L002, L004, L005, L007, L010, L012, L601, L605, and L606 to reflect changes in mail processing operations.

Release Notes
06/27/2025
USPS APIs Release Notes

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

Technical Specifications
06/27/2025
Enterprise Payment System IV-MTR Data Elements
Announcements
06/26/2025
INFORMATIONAL: Postal Service Prepares for Network Distribution Center Entry and Presort Discount Elimination
Contact Lists
06/26/2025
CASS™ Certified Products Guide: Residential Delivery Indicator Cycle O - (Expires July 31, 2028)
Contact Lists
06/26/2025
RDI™ Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)

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