If enabled, sent emails will include the recipient email address in the bounce/unsubscribe address field. This enables more accurate and more secure automated email handling. If using automated bounce/unsubscribe processing, enabling this option is strongly recommended.<br />
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This option requires that the specified account is a catch-all account or supports a "+" as a wildcard separator (such as in Gmail). For example, if this option is enabled with a bounce address of bounce@example.com, the email might be returned to bounce+123abc+user=domain.com@example.com.