2.2.3.1 PidTagReplyTime Property
Type: PtypTime ([MS-OXCDATA] section 2.11.1)
On a Draft Message object, if the sender desires to set a deadline for the recipient, the PidTagReplyTime property ([MS-OXPROPS] section 2.920) is set to the desired deadline, in UTC.
The server does not set the PidTagReplyTime property.