Announcements
10/23/2025
DELIVERY - Southern Area - South Carolina District - Clearwater Post Office (29822) – Resumes Operations
Announcements
10/23/2025
INFORMATIONAL - Commercial System Releases – October 23, 2025
Announcements
10/23/2025
INFORMATIONAL - API Maintenance Release - Wednesday, October 29th, 2025
Contact Lists
10/23/2025
CASS™ Certified Products Guide: Residential Delivery Indicator Cycle O - (Expires July 31, 2028)
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10/23/2025
RDI™ Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)

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

FAQs
10/23/2025
First-Class Mail and Marketing Mail Growth Incentives FAQs

On September 27, 2023, the Postal Regulatory Commission (PRC) approved the Postal Service request to make Mail Classification Schedule (MCS) changes to establish two distinct Mail growth incentives — a First Class Mail Growth Incentive and a Marketing Mail Growth Incentive. The incentives will run concurrently from Jan. 1, 2025 through Dec. 31, 2025. The following are some frequently asked questions and answers on these incentives.

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10/23/2025
CASS™ Certified Products Guide: M L O C R Mailers/Users Data File Cycle O - (Expires July 31, 2028)
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10/23/2025
CASS™ Certified Products Guide: M L O C R Mailers/Users Cycle O - (Expires July 31, 2028)
Contact Lists
10/23/2025
CASS™ Certified Products Guide: M L O C R Service Bureaus Data File Cycle O - (Expires July 31, 2028)
Contact Lists
10/23/2025
CASS™ Certified Products Guide: M L O C R Service Bureaus Cycle O - (Expires July 31, 2028)