value
Since: Version 2025.10.06-5ec871ab
The functionality described in this section requires version 2025.10.06-5ec871ab of KumoMTA, or a more recent version.
Depending on the header name, returns one of the structured representations of the header value.
If there is no defined header name and structured representation, the fallback behavior is to return the same value that you'd see if you accessed header.unstructured.
Note
For the sake of forwards compatibility, it is possible that we will add
support for names and structured representations in future versions. In that
scenario, if you were using header.value and relying on it returning
the same value as header.unstructured then your logic may be broken
by upgrading.
With that in mind, we recommend that you explicitly use header.unstructured
in your code for headers that are not included in the table below, rather
than relying on the fallback behavior.
Supported Header Names and Types
If the Since column is blank, it is assumed to be since the inception of header.value,
which is the version shown at the top of this page.
| Name | Equivalent field accessor | Since |
|---|---|---|
| Authentication-Results | authentication_results | |
| Bcc | address_list | |
| Cc | address_list | |
| Comments | unstructured | |
| Content-Disposition | mime_params | |
| Content-Id | message_id | |
| Content-Transfer-Encoding | mime_params | |
| Content-Type | mime_params | |
| From | mailbox_list | |
| Message-ID | message_id | |
| Mime-Version | unstructured | |
| References | message_id_list | |
| Reply-To | address_list | |
| Resent-Bcc | address_list | |
| Resent-Cc | address_list | |
| Resent-From | mailbox_list | |
| Resent-Sender | mailbox | |
| Resent-To | address_list | |
| Sender | mailbox | |
| Subject | unstructured | |
| To | address_list |