After proper configuration of email handler, it is possible to use Email Task in version 2.4.x to receive messages. To have it working correctly, "Email Task handler" must be selected in "Incoming Mail". To do so, whilst being logged as Jira administrator follow the below steps:
...
It is necessary for the reply-to field (i.e. in MS Outlook), to contain email address (3↑), tied with Email Task handler. By the rule and following the safest way, it should be a one used by Jira's POP/IMAP server - if it won't be exact, then emails with replies sent to a different email address simply will not be delivered to the handler and thus displayed in the "Emails" tab view. As a final step, please double check if created email handler's (2↑) email address, matches a one of POP/IMAP server (3↑). This should be done after following the below described, remaining steps 4 and 5.
...
To get optimal visual appearance of this add-on's feature, it is advised to use text only format.
Overview of "Emails" tab (1) of an Jira issue, to which Email Task was used to send emails and where to some of the messages:
Response was received in a standard "reply-to" (7) way, as well as via "Forward to" way to the original sender (6), moreover there's an easy way to spot, to which of the sent messages response hasn't been delivered yet - those are marked with similar arrows ⯯ (2) pointing downwards. For those messages to which reply has been received you can expect to see pointing upwards ⯭ (3). Threading of the messages is also preserved. Replies are placed further the center of the screen (5), than originally sent messages (4). As mentioned above you can expect to receive replies in a plaintext format (7). The same goes for forwarded messages to the original sender (6)
%20-%20overview%20of%20emails%20tab%20with%20standard%20reply%20to%20and%20forwarded%20replies.png?version=2&modificationDate=1527502103512&cacheVersion=1&api=v2)
As for the detailed content analysis:
After extending the view to see more details (1), you can see how the delivered message is too look (3). As one can see in both cases - message sent (2) and message received (5), it looks the same, as HTML email format is not yet supported in Email Task current version.
Please note that of course if a recipient's email client supports HTML display, then it is to look different than in Email Task, with all details of the original message preserved.
Replies delivered to Jira's mail handler and then displayed in Email Task, are displayed the same way as an original ones - by clicking the small arrow pointing downwards located left to the sent message (4)
%20-%20original%20message%20and%20reply.png?version=1&modificationDate=1527500223016&cacheVersion=1&api=v2)