Hi Devs, I just implemented logic to do $subject. The fix was pushed to stratos-4.1.x branch with the following commit revision:
https://github.com/apache/stratos/commit/597437184ab50b24eab7caf027db3147bf4cb617 JIRA: https://issues.apache.org/jira/browse/STRATOS-1557 Thanks -- Imesh Gunaratne Senior Technical Lead, WSO2 Committer & PMC Member, Apache Stratos