2.2.2.7 PidTagOriginalSenderEmailAddress Property
Type: PtypString ([MS-OXCDATA] section 2.11.1)
The PidTagOriginalSenderEmailAddress property ([MS-OXPROPS] section 2.834) is set on delivery report messages to the value of the original message sender's PidTagSenderEmailAddress property (section 2.2.1.49).