Set outlook X-Priority header for High Importance

Scenario

You want to be able to show a given email notification in the Outlook client with High Importance.

Solution

 Since JEMH 2.0

JEMH has custom email notification template support through Template Sets that are copies of the underlying Jira templates in Velocity Markup.  Within a custom TemplateSet, you have access to a particular helper class that allows exact mail headers to be set, which enable extra headers to be set ( Do not try to set To/Cc/Bcc this way!).

Example Script