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prepend_header

message:prepend_header(NAME, VALUE)

Constructs a header from NAME: VALUE and prepends it to the message content.

The VALUE is taken as-is and used as the header value.

Since: Version 2025.12.02-67ee9e96

The functionality described in this section requires version 2025.12.02-67ee9e96 of KumoMTA, or a more recent version.

This method now accepts an additional optional ENCODE parameter, which should be a boolean value:

message:prepend_header(NAME, VALUE, ENCODE)

When ENCODE is set to true then the VALUE will be encoded:

  • If the header value is ascii then it will be soft wrapped at whitespace around 75 columns, and hard-wrapped regardless of whitespace at 900 columns.
  • If the header value is non-ascii then it will be quoted printable encoded using RFC 2047 header encoding.