Main 800-524-0380
Technical Support 800-477-3602


**Note:** For some users with Windows Defender, there is a chance you may receive a false positive virus alert when downloading the file from your browser. The recommended workaround is to temporarily disable Windows Defender long enough to download the file then re-enable. You can then manually scan the downloaded file with Windows Defender (or other A/V program of your choice) and the file should scan successfully. We have reported this false positive to MS/Windows Defender and hope they will resolve the issue soon.

Review the product Release Notes pertaining to installation PRIOR to downloading and running any updates.

Software Prerequisites

DAT-MAIL requires Microsoft® .NET Framework 4.5.2 as a prerequisite.

Please see the following prerequisite resources:


NOTE: For the most complete and up-to-date requirement information, refer to the "Window Book Product Requirements Guide."

Learn More about DAT-MAIL

Learn More about DAT-MAIL Network Auto-Update System

Latest DAT-MAIL™ MS-SQL Product Version

Download DAT-MAIL™ (64-bit)

Release Notes

All Release Notes


NOTE: This is a Mandatory Release for USPS competitive products. It contains the new Postal Rate seasonal surcharges effective October 3 through December 25, 2021.


The following USPS competitive products are affected by the surcharge:


  • Priority Mail

  • Priority Mail Express

  • First-Class Package Service



  • Parcel Select


        Destination Entry

        Lightweight Parcels

  • USPS Retail Ground

  • Parcel Return Service


A reminder that PostalOne! does not allow a single mail.dat to have multiple partial RTP submissions that span both rate cases.  All partial RTP submissions within a mail.dat job must have ALL the CSM Postage Statement Dates either before or after the date of the price change. 


Known Issues:





T21707, T21708, T21709:  DAT-MAIL price adjustments for the USPS 2021 Peak Season Surcharge effective for the period 10/3 thru 12/25/21.



Bug Fixes:


B21752:  A client reported an issue where the updated certificate fee was not applied on the PS-Form 3606-D.   This was investigated, confirmed and has been corrected. Ticket 97799


B21845:  An issue was reported by a client where they found that DAT-MAIL was not populating the B14 rate on the statement for First Class flats. This was reproduced in testing - although the B14 rate did populate on the rate summary report it was missing on the statement.  This has been corrected.  Ticket 98277








Bug Fixes: