Migration date appearing on destination emails – CloudM

Problem

Sometimes, the migration date will appear on some emails after the migration.

Reason

This happens when mail from the source has an invalid DATE: header - "invalid" meaning not compliant with RFC822. We modify these messages by default to ensure they are migrated.

If you do not want the messages to be modified,

On the Config Settings screen, select Advanced Settings > Email > Modify Invalid Messages
Set to Disabled.

This will cause the message to not be modified and it will fail the migration (as it will have an invalid DATE: header).