Starting with September data, published on August 1, the Postal Service will be changing the frequency of updates to labeling lists and the Mail Direction file. Originally, the new monthly schedule was slated to start in with July data, published on June 1. However, with the delay of the summer PostalOne! release to August/September, the monthly data update was postponed as well.

The Importance of Presort Data Files The labeling list and mail direction file data is used by presort and post-presort software to create correct containers, qualify mail for entry discounts and determine drop shipment locations. In addition, the Zone Charts, City/State file and Delivery Statistics file will also be released according to the new schedule. When this data is incorrect or out of date, containers can be shipped to the wrong USPS facility and delivery can be delayed. In extreme cases, drop shipments can be rejected when shipped to the wrong location.

About the Change USPS has changed the frequency of data file updates several times over the past several years. Most recently, these files were updated quarterly. However, due to the number of facility closures and the need to more dynamically update processing of five-digit schemes, the Postal Service determined that it needs to be able to update these files more frequently to better match their constantly changing processing network. On August 1, USPS will start publishing these files every month. Each file will have a three-month time span. When the data is published in the first month, this will serve as a notification period - mailers can install the file, but not use it for current mailings. The next month, the file will be usable for any and all mailings. The file will expire in the third month, and can be used for mailings entered through the end of the month. This means that in any given month, there will be three valid files: two that can be used for active mailings, and one "notification" file that can be used to prepare mailings for the upcoming months.

Here are some scenarios to consider:
- If it's November 8 and you're preparing a mailing for today, the November data published on October 1, or the older October data published on September 1, can be used for this mailing. The December data, published November 1, can't be used at this time.
- For a mailing prepared in early December, you'll need to use the already-published December data published on November 1 or the November data published on October 1.
- If you're preparing a January mailing in November, your only option is to use the December data that was published on November 1.
- Preparing mailings that are more than three months in advance is not advised. There's a good chance you won't have valid data available for your intended mailing date.

Currently, your mailings are compared to the active presort files when your mailing is verified. Starting in October, USPS will start checking the files when the mail is inducted, rather than at mail verification. If you drop ship your mail, you will need to ensure that the proper files are used, especially near the end of the month. If you presort and prepare your mailing in advance, the window for preparing those mailings is shrinking. Fortunately, any errors in preparation will be evaluated based on the make-up of the mail, not strictly the mailing date. This means that if you're sending mail to areas not affected by labeling list changes, your mail will not be reported as being prepared incorrectly.

If any errors are found, your mail should not be rejected. Instead, the errors will appear in your Mailer Scorecard on the Business Customer Gateway. Monitor your Scorecard to ensure that you are compliant, as fines may be assessed in the future.

How to keep up to date You'll need to make sure these files are updated monthly in both your presort and post-presort software products to meet the new schedule requirements. Each software solution has a different way of updating this data, so you'll want to contact your software provider to get more information.