The Z4CHANGE product provides mailers the information necessary to create an application that will facilitate frequent and cost-effective processing for updating very large computerized mailing lists for automation compatibility and improved deliverability.

Current USPS regulations require that all customer address lists be processed by CASS Certified™ address-matching software (see Domestic Mail Manual (DMM), section A708 for a complete description of CASS requirements). CASS-certified software applies the correct ZIP+4®, delivery point, and/or carrier route codes while standardizing the address, city, and state elements. To enhance deliverability, the USPS recommends that customers reprocess their address lists more frequently using CASS Certified software; however, frequent reprocessing of address lists can be costly and time-consuming.

Z4CHANGE was developed for customers who need data as a cost-effective means of improving the deliverability of their mail using the most current ZIP+4 and delivery point information. Z4CHANGE helps customers achieve this goal by providing data that indicates which ZIP+4 codes have been realigned in the past twelve months. When a high-rise (“H”) or firm (“F”) record is added to the ZIP+4 product by the USPS, Z4CHANGE also shows a transaction for the supporting street ZIP+4 code, allowing customers the opportunity to upgrade previously-coded street-level matches. Customers must then develop their own software to access Z4CHANGE to determine which records on their address lists need to be reprocessed by CASS Certified software. As a result, only the records that have had transactions will need to be reprocessed, which can be done monthly or bimonthly.

Should the USPS determine that a significant change in CASS™ requirements warrants a complete update of all addresses, Z4CHANGE customers may be notified that they will be required to reprocess their entire address lists. Otherwise, Z4CHANGE customers will only be required to reprocess their entire address lists at the end of the third year following Z4CHANGE certification.


The Z4CHANGE product and CASS certification offer the following benefits:

Consider Z4Change which can speed up the CASS process in AccuZIP6 5.0 to upwards of 25,000 per second. The Z4Change product looks at the previously CASS certified records and the new CASS data and determines which ZIP+4 have activity and only reprocessed those records, which is about 5% each month. Z4Change will greatly enhance the speed of processing CASS + NCOALink and cut down the time from hours to minutes or days to hours.

To place an order or learn more about Z4Change, call (800) 233-0555.

AccuZIP Inc. is a nonexclusive Limited Service Provider Licensee o f the United States Postal Service (USPS®). Its product and service prices are neither established, controlled, nor approved by the USPS. The following trademarks are owned by the United States Postal Service: USPS, ANKLink, NCOALink , United States Postal Service, CASS, PAVE, CASS Certified, Standard Mail, First-Class.