I have a custom workflow in SharePoint 2013. The workflow sends emails to users. Our employees use Outlook, and after opening the emails, they always retain the "Unread" icon, which has led to confusion and complaints.
The cause of the problem is detailed here. In short, Outlook icons only work with Message Class = IPM.Note. Somehow, SharePoint is sending emails with a different Message Class = IPM.Note.Custom.Microsoft.Workflow.2013.
We would like SharePoint to simply send normal email formats. Is there any way to prevent SharePoint from using this strange Message Class?
