1.3.3 Property ID Ranges
The 65,536 possible values of the property ID are divided into sub-ranges reserved for various purposes, as described in the following table.
In this context, the term "non-transmittable" refers specifically to transmission via an email transport protocol (such as SMTP), and not to any network transport protocol (such as TCP):
Servers do not allow property IDs in ranges specified as non-transmittable to be submitted for transport to another server via an email transport protocol. Property IDs in ranges not specified as non-transmittable are submitted for transport to another server.
Clients can use properties in ranges described as message class-defined for application-defined purposes. When doing so, applications specify a value for the PidTagMessageClass property (section 2.789) that is distinct from any value listed in section 1.3.1.
Clients can use any named property for application-defined purposes. No constraint is placed on the value of the PidTagMessageClass property in this case, but the property set of the named property is distinct from any value listed in section 1.3.2. Note that named properties are transmittable.
Clients can use properties in ranges specified as transport-defined, but they cannot define new properties in those ranges.
Clients can use and define properties in ranges specified as user-defined, but need to avoid conflicts with alternate definitions of the same property ID.
Range minimum
Range maximum
Description
0x0001
0x0BFF
Message object envelope property; reserved
0x0C00
0x0DFF
Recipient property; reserved
0x0E00
0x0FFF
Non-transmittable Message property; reserved
0x1000
0x2FFF
Message content property; reserved
0x3000
0x33FF
Multi-purpose property that can appear on all or most objects; reserved
0x3400
0x35FF
Message store property; reserved
0x3600
0x36FF
Folder and address book container property; reserved
0x3700
0x38FF
Attachment property; reserved
0x3900
0x39FF
Address Book object property; reserved
0x3A00
0x3BFF
Mail user object property; reserved
0x3C00
0x3CFF
Distribution list property; reserved
0x3D00
0x3DFF
Profile section property; reserved
0x3E00
0x3EFF
Status object property; reserved
0x4000
0x57FF
Transport-defined envelope property
0x5800
0x5FFF
Transport-defined recipient property
0x6000
0x65FF
User-defined non-transmittable property
0x6600
0x67FF
Provider-defined internal non-transmittable property
0x6800
0x7BFF
Message class-defined content property
0x7C00
0x7FFF
Message class-defined non-transmittable property
0x8000
0xFFFF
Reserved for mapping to named properties. The exceptions to this rule are some of the address book tagged properties (those with names beginning with PIDTagAddressBook). Many are static property IDs but are in this range.