Specifies that a notification should be sent to a user. The format of the notification is implementation-defined and is affected by the notification method used.
The notification method is identified by a URI. For example, the notification method can be a tel URI [TEL-URI] with a phone number to send SMS messages to, or an XMPP [XMPP] URI containing an XMPP identifiers [XMPP-URI]. The supported notification methods are site-specific, but support for the [MailTo] method is guaranteed.
Sieve scripts should check the supported methods using the valid_notify_method test to be sure that they only use supported ones.
An implementation may enforce semantic restrictions on URIs. For example, to restrict phone numbers in a tel URI to a particular geographical region. This will cause a parser error.