In this release, there are two notification services for event notifications and alarms: Sun Java System Message Queue (JMQ) and Event Notification Service (ENS). In a future release, the Communications Suite products will use JMQ exclusively and ENS will be deprecated. However, for this release, Messaging Server, Calendar Server, and Instant Messaging still have internal dependencies to ENS; therefore, you can continue to use ENS.
For this release, the Messaging Server IMAP IDLE feature requires the use of ENS. Messaging Server has no other dependencies on ENS. If you do not use IMAP IDLE, you can use JMQ exclusively for event notifications.
If you want to use IMAP IDLE, you must configure an ENS notification plug-in. You can also use JMQ for message notifications by configuring a JMQ notification plug-in. (Messaging Server allows you to configure multiple notification plug-ins.