Announcements
10/26/2026
Delivery - Hughesville Post Office (20637) - Resumes Operations
Announcements
10/26/2026
INFORMATIONAL - Scheduled Maintenance for November 14, 2026 – Possible Disruption with USPS Payments API
FAQs
10/26/2026
USPS Fuel Surcharge Implementation-Frequently Asked Questions

The USPS is creating a Fuel Surcharge, which will be charged on all competitively priced packages and calculated as a percentage of the base postage.  The surcharge will be updated weekly, based on the prices of diesel and jet fuel, as described on the eia.gov website.

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 - USPS APIs System Release Notification - REVISED
Announcements
10/23/2026
INFORMATIONAL - Oracle PSU Patching - PPI, PASS, MANIF, GEO, and ADP
Announcements
10/23/2026
INFORMATIONAL - Commercial System Releases – October 28, 2026 and November 1, 2026
Announcements
10/23/2026
INFORMATIONAL - PostalOne! Alert – October 25, 2026
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
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

Release Notes
10/23/2026
Informed Visibility® Mail Tracking & Reporting (IV®-MTR) Release Notes

These release notes summarize new features and enhancements implemented in deployments to the IV-MTR application.

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)
Contact Lists
10/22/2026
CASS™ Certified Products Guide: M L O C R Mailers/Users Cycle O - (Expires July 31, 2028)
Contact Lists
10/22/2026
CASS™ Certified Products Guide: M L O C R Service Bureaus Data File Cycle O - (Expires July 31, 2028)
Contact Lists
10/22/2026
CASS™ Certified Products Guide: M L O C R Service Bureaus Cycle O - (Expires July 31, 2028)
Contact Lists
10/22/2026
CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Data File Cycle O - (Expires July 31, 2028)
Contact Lists
10/22/2026
CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Cycle O - (Expires July 31, 2028)
Contact Lists
10/22/2026
CASS™ Certified Products Guide: Z4CHANGE Data File Cycle O - (Expires July 31, 2028)
Contact Lists
10/22/2026
CASS™ Certified Products Guide: Z4CHANGE Cycle O - (Expires July 31, 2028)