Message-ID: <42@example.org> Date: Mon, 20 Oct 2015 12:41:49 +0100 From: John Doe MIME-Version: 1.0 To: alice@example.org Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 8bit Subject: =?iso-8859-15?q?Subject_with=0Bcontrol_character?= This is a message containing a MIME-encoded control character in the subject line.