Hi, AFAIK currently we are not using $subject. But it is mentioned in the [1] point #12. This feature can be fully tested and added in future.
[1] https://cwiki.apache.org/confluence/display/STRATOS/4.0.0+Cartridge+Agent+Lifecycle Thanks -- *Dinesh Bandara* Software Engineer WSO2 Inc.; http://wso2.com lean.enterprise.middleware
