What does this OID means ?

Hello All,

In the S/MIME signed message with MS Outlook, there are 5 signed
attribues.

Each attribute has Object Identifier and it is defined PKCS #9 v2.0,
but  one attribute which has
{1 3 6 1 4 1 311 16 4} as OID is not defined anywhere.

What does this OID means ?

Thank you.

Chung