2.1.3.1.5 Return Receipt
A MIME writer generates a (nonstandard) Return-Receipt-To header when the PidTagOriginatorDeliveryReportRequested property ([MS-OXOMSG] section 2.2.1.20) is set to TRUE.
If the PidTagOriginatorDeliveryReportRequested property is set and its value is TRUE, MIME writers SHOULD copy the Return-Receipt-To header from one of the following property groups in the specified order of priority and according to the method specified in section 2.1.3.1.1:
PidTagReadReceipt property group (section 2.6.1)
PidTagSender property group (section 2.6.4)
PidTagSentRepresenting property group (section 2.6.5)
A MIME writer MAY<15> copy the values in the PidTagSentRepresenting property group to the Return-Receipt-To header, regardless of the values of the other properties.
When generating a TNEF message, MIME writers SHOULD<16> copy the values of the PidTagOriginatorDeliveryReportRequested property and one of the e-mail address properties specified in the previous list to the attMsgProps attribute, as specified in [MS-OXTNEF] section 2.1.3.3.21, in the TNEF body part.