Bidirectional email channels in Jira includes a mail handler that processes incoming emails. These emails are either transformed to new issues or to comments. The emails are often replies to notifications including old content which would be ideal to get rid of when the email is converted to comments.

Email This Issue Mail Handler supports Split Regex, a regular expression based pattern matching technique to find a delimiter to split email body to old and new content. 

Finding a reliable pattern in reply emails is not easy, and is dependent on the email clients used to reply to old emails.

Visible Content Marker

One trick which guarantees the best results is:

• add the delimiter to your email templates in Email This Issue, like --Please reply above this line--
• add regular expressions that matches this delimiter: /--Please reply above this line–/

Invisible Content Marker

If you do not want to add a visible and readable content marker as above, you can add an invisible HTML tag and match it in the regular expression

• add the delimiter to your email templates in Email This Issue, like <div class="jeti-reply-marker"></div>
• add regular expressions that matches this delimiter: /\<div class=\"jeti-reply-marker\"\>\<\/div\>/