Release Notes
03/13/2026
March 22 2026 Release Notes
Announcements
03/06/2026
INFORMATIONAL - Commercial System Releases – March 8, 2026
Release Notes
03/06/2026
PTR2 Release Notes_DD_03_07_26
Announcements
03/06/2026
INFORMATIONAL- 2026 National Postal Forum - Workshop Schedule Is Available Online
FAQs
03/06/2026
USPS PTR2 API Known Issues
Announcements
03/05/2026
INFORMATIONAL - End of USPS Web Tools Tracking 3.5.26
Contact Lists
03/05/2026
CASS™ Certified Products Guide: Residential Delivery Indicator Cycle O - (Expires July 31, 2028)
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03/05/2026
RDI™ Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)

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

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03/05/2026
CASS™ Certified Products Guide: M L O C R Mailers/Users Data File Cycle O - (Expires July 31, 2028)
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03/05/2026
CASS™ Certified Products Guide: M L O C R Mailers/Users Cycle O - (Expires July 31, 2028)
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03/05/2026
CASS™ Certified Products Guide: M L O C R Service Bureaus Data File Cycle O - (Expires July 31, 2028)
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03/05/2026
CASS™ Certified Products Guide: M L O C R Service Bureaus Cycle O - (Expires July 31, 2028)
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03/05/2026
CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Data File Cycle O - (Expires July 31, 2028)
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03/05/2026
CASS™ Certified Products Guide: M L O C R Hardware Manufacturers Cycle O - (Expires July 31, 2028)
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03/05/2026
CASS™ Certified Products Guide: Z4CHANGE Data File Cycle O - (Expires July 31, 2028)
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03/05/2026
CASS™ Certified Products Guide: Z4CHANGE Cycle O - (Expires July 31, 2028)
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03/05/2026
CASS™ Certified Products Guide: Vendor/Service Licensees Data File Cycle O - (Expires July 31, 2028)
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03/05/2026
CASS™ Certified Products Guide: Vendor/Service Bureaus Licensees Cycle O - (Expires July 31, 2028)
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03/05/2026
CASS™ Certified Products Guide: DSF2® Licensees Data File Cycle O - (Expires July 31, 2028)
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03/05/2026
DSF2® Licensees Cycle O: Certified Products Guide - (Expires July 31, 2028)
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03/05/2026
DPV® Licensees Data File Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)
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03/05/2026
DPV® Licensees Cycle O: Certified Products Guide - (Expires July 31, 2028)
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03/05/2026
CASS™ Software Manufacturers Data File Cycle O: Certified Products Guide (D) - (Expires July 31, 2028)
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03/05/2026
CASS™ Software Manufacturers Cycle O - (Expires July 31, 2028)
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03/05/2026
CASS™/MASS™ Certified Products Guide - All Sections Data Files Cycle O - (Expires July 31, 2028)

This document contains the certified vendors list for CASS™ and MASS™ products for Cycle O.