AUTH extension. You can use SupportedAuthenticationMethods()()()() to obtain all authentication methods supported by the remote server.

ID extension is supported. (http://www.faqs.org/rfcs/rfc2971.html)

IDLE extension. You can use Idle()()()() or Idle(TimeSpan) to wait for mailbox changes. (http://www.faqs.org/rfcs/rfc2177.html)

IMAP4rev1 is supported.

Login is disabled. Login(String, String) is going to invoke UseBestLogin(String, String) method. (http://www.faqs.org/rfcs/rfc2595.html)

NAMESPACE is supported. You can use GetNamespaces()()()()method. (http://www.faqs.org/rfcs/rfc2342.html)

QUOTA is supported. You can use GetQuota(String) and GetQuotaRoot(String) methods.

SASL-IR (SASL initial client response) extension is supported. Servers which support this extension will accept an optional initial client response with the AUTHENTICATE command for any SASL mechanisms which support it. (http://www.faqs.org/rfcs/rfc4959.html)

SORT is supported. You can use Sort(ISorter) to sort search results. (http://www.faqs.org/rfcs/rfc5256.html)

SPECIAL-USE extension is supported. Servers which support this extension will return new folder flags identifying Special-Use folders. (http://tools.ietf.org/html/rfc6154)

STARTTLS is supported. You can use StartTLS()()()() to secure the connection. (http://www.faqs.org/rfcs/rfc2595.html)

UIDPLUS extension. You can use return value of UploadMessage(String, IMail), UploadMessage(String, String), copy and move methods. (http://www.faqs.org/rfcs/rfc4315.html)

Identifies Gmail X-GM-EXT-1 extensions: X-GM-RAW, X-GM-MSGID, X-GM-THRID, X-GM-LABELS. ,

XLIST command is supported. You can CommonFolders class to get common folder names (e.g. Spam, Sent items).