Make configurable behaviour of "Reply-To" email header in JSM customer notifications

Summary

As for the current versions (e.g. 4.22.2), when you have one or more “Email channels” configured for your Jira Service Management (JSM) project, the generated email notifications will have a “Reply-To” email header with the email address value of Email Channel.

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Date: Tue, 21 Jun 2022 10:38:00 +0000 (UTC)
From: "admin (Jira)" <jira_smpt_outgoing@email.local>
Reply-To: email_request_channel_0@email.local
To: admin@email.local
Message-ID: <JIRA.10100.1655807629000.3.1655807880000@Atlassian.JIRA>
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References: <JIRA.10100.1655807629000@Atlassian.JIRA> <JIRA.10100.1655807629162@9d60ecdfb411>
Subject: ITSD-42 Testing email channels

When you reply to such notification in your email client, instead of putting the email address from “From” it will use the address that was configured for "Reply-To" (i.e. JSM “Email Channel” address). This is expected as per rfc822.

However, if you will have more than one JSM “Email Channel” configured, it is not guaranteed that generated notifications will have the exact channel's email address in "Reply-To" (based on the issue's "Request Type" or some other condition) — just first found the address from first email channel will be used.
Also, if you update the JSM ticket with “Request Type” NOT associated with any JSM "Email Channel", it will still receive one of the channels' email addresses in the “Reply-to” header.

This behaviour is not impacting notification processing functionality — no matter what “Email Channel” will receive replied email it will be still processed accordingly.

Potential issues

Despite being 'harmful' from a functionality perspective, this behaviour makes customers lose control over user responses since it is a little bit ‘unpredictable’ which address users will send the email to when they reply to the notification. For example, if the customer has both JSM “Email Channel” and Jira Incoming mail handler configured, the notification sent for the JSM issue will receive the channel’s “Reply-To” address and, hence, upon response email will not reach the expected (from a logical point of view) Incoming handling mailbox.

Suggestion

1. Make it possible to configure the behaviour of the "Reply-To" header for JSM email notifications (enable/disable/substitute with desired value).
   • Alternatively, it would make sense to override the "Reply-To" value with settings defined for the address configured in the notification scheme.
2. Implement more strict and predictable logic for assigning email addresses to the "Reply-To" header in case of multi-channel project configuration.