2.2.15 [RFC3501] Section 6.2.3, LOGIN Command
The specification states: "A server MAY include a CAPABILITY response code in the tagged OK response to a successful LOGIN command in order to send capabilities automatically."
Microsoft Exchange Server 2007, Microsoft Exchange Server 2010, Microsoft Exchange Server 2013
Microsoft Exchange Server does not include a CAPABILITY response code in its response to a successful LOGIN command. Microsoft Exchange sends capabilities only in response to a CAPABILITY command from the client. For more details, see sections 2.2.13, 2.2.14, and 2.2.30 of this document.