Mailer sends messages in MIME format (a published standard officially known as RFC 1521 or RFC-MIME). If your email recipients see confusing codes like =20 or =09 in the messages that you send, their mail applications are not MIME-compliant.
You can solve this problem by having your email recipients use a MIME-compliant mail application. If that is not possible, then send your email in Sun Mail Tool format. However, most MIME-compliant mail readers do not understand this proprietary format.
Choose Send As from the Compose File menu.
Choose either Internet MIME or Sun Mail Tool from the submenu.
Your message is sent in the selected format.
If you do not specify a format, the default is Internet MIME. To change this default: