USPS PostalOne! Mail.dat Client Update

Effective: September 18, 2022

Dear Mailers Customer: 

The USPS® is requiring a PostalOne!® Mail.Dat® Client Update that takes effect on Sunday, September 18, 2022.

Who does this affect?
This affects Presort Object, Mailers+4 Desktop and Mailers Online customers that upload Mail.dat files to PostalOne!

How to download the new Mail.dat client:
The new Mail.dat Client ( can be downloaded from the USPS® Business Customer Gateway by performing the following steps:

  1. Go to USPS® Business Customer Gateway (BCG) website and click “Sign in to the BCG” to log in to your account.
  2. Click “Dashboard” under Favorite Services to the right of the webpage.
  3. Click “Electronic Data Exchange” under Manage Mailing Activity in the top left.
  4. Download the Mail.dat Client Application under “Mail.dat Support for Production” for your Operating System (32-bit or 64-bit).

For more information about the upcoming Mail.dat Client update, please visit:

For any questions, please email us at or call 1 (800) 800-6245 option 4.

Thank you,

The Melissa Team

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