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Notification-Delay Header

Exchange Server 2003

Notification-Delay Header

This content is no longer actively maintained. It is provided as is, for anyone who may still be using these technologies, with no warranties or claims of accuracy with regard to the most recent product version or service release. The WebDAV Notification-Delay header is used in the SUBSCRIBE Method and specifies the delay the client would like the server to use in processing events. This only applies to callback notifications.


Notification-Delay:= "Notification-Delay:" 1*DIGIT

If the SUBSCRIBE Method request does not also include a Call-Back Header, the Notification-Delay header is ignored.

If the client explicitly requested a notification delay, the server must include in its response an identical header containing the notification delay that it will use. The server may return a value that is greater or less than the value requested by the client, allowing the server to dictate a minimum delay, a maximum delay, or to return a less granular delay. For example, the server may round up a request from 0.24 to 0.25.

The header is also valid in a subscription refresh and indicates a request to change the notification delay. If the server does not support changing the notification delay but otherwise will refresh the subscription, it must respond with a 200 (OK) response, and include the Notification-Delay header with the original value.


The following subscription will coalesce events for 400 seconds before sending a notification to the User Datagram Protocol (UDP) server that was specified in the Call-Back header.

SUBSCRIBE /public/subtest HTTP/1.1
Notification-type: update
Notification-Delay: 400
Call-Back: httpu://