Emoji markers add emojis to the Slack message based on specific criteria. Eg: when issues are created, assigned or closed, the relevant emojis will be added on the message. Emojis will also be added to all the issues which are unattended for 5mins. You can enable and customize the emoji markers in Troopr Webapp.
To enable this feature, go to: Troopr webapp-> Projects-> Channel-> Emoji markers.