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.

February 2026 Nixie Volume

This spreadsheet contains the UAA statistics for February 2026.

Informed Visibility Mail Tracking & Reporting Machine Count

List of US Postal Service machines by site, including a description of each machine.

ZIP Codes by Area and District codes

The Excel spreadsheet lists ZIP Codes with the associated Area and District Codes.  

***Updated - New Areas*** - Area District 5-digit ZIP Codes (AREADIST_ZIP5.TXT)

USPS Ship Data Dictionary

Detailed information on the USPS Ship (Formerly Package Platform) data elements available through the Informed Visibility Mail Tracking & Reporting (IV-MTR) application. Please note that items in bold text were updated or added recently.

Automated Zone Indicator (AZI) Table

The AZI table lists each five-digit ZIP Code™ and is an indicator of the type of processing that typically takes place on letter mail destined for each ZIP Code. Each number in the file is a ZIP Code appended with a numeric zone indicator. The five numeric indicators are as follows:

1. Two Pass Zones: Automated two-step sector/segment at mail processing facilities
2. 876 Carrier Route Sort Zones: Automated incoming secondary carrier route sorting at plants
3. Carrier Route Barcode Sorter (CSBCS) Zones: Automated walk sequence sorting on CSBCS machines at delivery units
4. Delivery Barcode Sorter (DBCS) Zones: Automated walk sequence sorting on DBCS machines at plants [i.e., sectional center facilities (SCFs)] or at delivery units
5. Manual/Mechanized Zones: No automated sorting; no tracking code scans should be generated from facilities matched to these ZIP Codes

City/State ZIP Code Weekly Compare

3 Digit ZIP/AISU Office List (AISUREPT.TXT)

AIS Congressional District File (CONG_DIST.TXT)

AIS County Name Table Layout (AISCNTY.TXT)

AMS County Name Table (COUNTY_NAME_TABLE.TXT)

AMS Address Report: AISU Mailing List (ADDRREPT.TXT)

AISU ZIP Code Record and AISU Address Record Descriptions (AISULOUT.TXT)

AISU ZIP Code File (AISUZIPS.TXT)

AISU Contact Information (AISUADDR.TXT)

Area District Finance File Specification (AREA_DIST_LAYOUT.TXT)

Area District Finance File (AREADIST.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.

Undeliverable-as-Addressed (UAA) Mail Roll-Up 1998-2025

Labeling List Changes Effective April 1, 2026

Effective April 1, 2026, the Postal Service™ will revise Labeling List(s) L002, L005, L007, L012, 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 April 1, 2026, effective date through May 31, 2026, expiration date. The changes will be published in the Postal Bulletin, Issue #22698.

Pending Route Adjustment File

This Excel sheet details route adjustments for February 2026 thru April 2026.

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®.

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.

January 2026 Nixie Volume

This spreadsheet contains the UAA statistics for January 2026.

Updated List: Service Type Codes for Intelligent Mail® Package Barcode (IMpb)

This document provides the updated service type codes for  Intelligent Mail® Package Barcodes.

Informed Visibility® Mail Tracking & Reporting (IV®-MTR) Operation Codes List

This spreadsheet provides a list of operation codes (opcodes), also known as Scan Event Codes, for the IV-MTR application.

ACS Tables: PARS 2025

This spreadsheet contains 12 tables outlining ACS volume and cost for UAA Mail from FY2025.

Base Tables: PARS 2025

This spreadsheet contains 44 base tables focusing on postal operations, cost, and volume of handling UAA mail from FY2025.

Class Tables: PARS 2025

This spreadsheet contains 64 class tables that provide cost and volume by class of mail, presort category, and shape from FY2025.

Volume Tables: PARS 2025

This spreadsheet contains 3 volume tables that provide summary data by class of mail, shape, presort category, and disposition of UAA Mail.

Undeliverable-as-Addressed (UAA) Statistics by Mailing Industry Quarterly Report (Q1 FY26)

ACS Nixie stats by industry for FY26 Q1.

December 2025 Nixie Volume

This spreadsheet contains the UAA statistics for December 2025.

Labeling List Changes Effective February 1, 2026

Effective February 1, 2026, the Postal Service™ will revise Labeling List(s) L002, L005, L012, 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 February 1, 2026, effective date through March 31, 2026, expiration date. The changes will be published in the Postal Bulletin, Issue #22694.

PTR2 Event Scripting Changes (Excel Document)

PTR2 Event Scripting Changes

NCOALink® Statistics

This spreadsheet includes NCOALink statistics from 2007-2025 by licensee type.

November 2025 Nixie Volume

This spreadsheet contains the UAA statistics for November 2025.

PTR Domestic Scan Events and Descriptions

October 2025 Nixie Volume

This spreadsheet contains the UAA statistics for October 2025.

ACS Tables: PARS 2024

This spreadsheet contains 12 tables outlining ACS volume and cost for UAA Mail from FY2024.

Base Tables: PARS 2024

This spreadsheet contains 44 base tables focusing on postal operations, cost, and volume of handling UAA mail from FY2024.

Class Tables: PARS 2024

This spreadsheet contains 64 class tables that provide cost and volume by class of mail, presort category, and shape from FY2024.

Volume Tables: PARS 2024

This spreadsheet contains 3 volume tables that provide summary data by class of mail, shape, presort category, and disposition of UAA Mail.

ACS Tables: PARS 2023

This spreadsheet contains 12 tables outlining ACS volume and cost for UAA Mail from FY2023.

Base Tables: PARS 2023

This spreadsheet contains 44 base tables focusing on postal operations, cost, and volume of handling UAA mail from FY2023.

Class Tables: PARS 2023

This spreadsheet contains 64 class tables that provide cost and volume by class of mail, presort category, and shape from FY2023.

Volume Tables: PARS 2023

This spreadsheet contains 3 volume tables that provide summary data by class of mail, shape, presort category, and disposition of UAA Mail.