User Guide
Here are instructions on how to use Email Notification Digest add-on.
Open your JIRA User Profile → Email Digest menu to configure your personal digest settings
The page will show how many notifications is already in the digest, allow you to preview the digest and tell the system to send Email Digest immediately.
In addition, you can change whether the plug-in should send digest to you, time slots in a week to send digest and the maximum limit of the amount of records in it.
Email Digest
You will receive digest email at a scheduled date/time if there is at least one update happened in JIRA where you are the watcher.
If there were no updates in JIRA then the digest email will not be sent.