2.2.1.10 PidTagNormalizedSubject Property
Type: PtypString ([MS-OXCDATA] section 2.11.1)
The PidTagNormalizedSubject property ([MS-OXPROPS] section 2.813) contains the normalized subject of the message, as specified in [MS-OXCMAIL] section 2.2.3.2.6.1. This property is set by the client but can be an empty string if there is no subject. The sum of the lengths of the PidTagNormalizedSubject property and the PidTagSubjectPrefix property (section 2.2.1.9) MUST be less than 254 characters.
More details about obtaining the value of this property are specified in section 3.1.5.13.