Migrating emails using SMTP resets timestamps

Avoid using Google SMTP servers to migrate message data into Gmail when your organization uses Vault. When data is sent through SMTP, the original date and time the message was received are overwritten with the migration date and time.

Workaround

To preserve the original timestamp data, use one of the following options:

1. Use a Google Workspace migration tool.
2. Use the Gmail API. The Gmail API has an insert option that lets you choose which date is used to enforce retention (the actual date header or the time the message was received). To use the API, use the users.messages.insert method with deleted: true. Learn more