Labeling List Changes Effective May 1, 2026

Effective May 1, 2026, the Postal Service™ will revise Labeling List(s) L007, L012, L014, L016, L051, L201, and L606 to reflect changes in mail processing operations. Mailers are expected to label according to these revised lists for mailings inducted on or after the May 1, 2026, effective date through June 30, 2026, expiration date. The changes will be published in the Postal Bulletin, Issue #22700.

Z4 Info File

A downloadable ZIP file containing information related to the Z4 Info File

Early Warning System (EWS002C0.ZIP)

This file is the EWS production file and is updated weekly. This file contains the Early Warning System data file for the CASS™ and MASS™ certification process.

Informed Visibility® Mail Tracking & Reporting (IV®-MTR) Development Tracker

This document provides a list of active IV-MTR work to be as well as items completed in FY25.

*Please note, Postal Pro is the only source for a current IV-MTR Development log as updates will be made on an ongoing basis.

City/State ZIP Code Weekly Compare

Area District Finance File Specification (AREA_DIST_LAYOUT.TXT)

Area/District 3-digit and 5-digit ZIP Code Assignments (AREA_DIST_ZIP.TXT)

Move to Competitive Street Addressing (MTC SA) List

This .txt file contains the MTC SA List.

Cumulative Listing of ZIP Codes Covered by the LACS Database

This document provides a cumulative listing of ZIP Codes covered by the LACS database for LACS^Link®.

February 2026 Nixie Volume

This spreadsheet contains the UAA statistics for February 2026.