USPS To Retire Mail.dat Version 19-1

The United States Postal Service is retiring Mail.dat Version 19-1, effective with the PostalOne! update scheduled for Sunday, December 26, 2021.

On that date, Mail.dat Version 19-1 files will only be supported for previously uploaded files that require updates. For new jobs being uploaded to PostalOne!, the supported Mail.dat versions will be 21-1 and 22-1.

What does this mean for mailers?

If LSC Communications (including Digital Lizard and Lakeside Book Company) is presorting your mailing lists and generating Mail.dat files that are uploaded to PostalOne!, you do not need to take any action. LSC Communications will take care of ensuring that the Mail.dat files for your mailing jobs are processed in the 21-1 version format.

If your mailing lists are presorted and Mail.dat files generated outside of LSC Communications (including Digital Lizard and Lakeside Book Company), please contact your presort provider to request that Mail.dat files for your mailing jobs be generated in the 21-1 version format by December 26, 2021.

Details of the December 26, 2021 PostalOne! Release notes may be found on PostalPro.

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