I hate to admit it, but MS Outlook has a very handy feature: one can not only flag emails as todo, but also check them off once this email (or a task behind) is done. At the office i am working on Windows 10 and latest version of outlook, emails are synced over an exchange server. From home and on the go I use to use my MacBook (running OS X) to access the same emails using Mail. Is there any known way to make Mail also support these checkmark added to emails? (e.g. by plugins) If I mark an email with a flag in either Mail or Outlook, this flat is perfectly synced across all other mail clients. I wished same was true for the checkmark, but it seems Mail does not understand this one out of the box. Or is there a way to somehow hack support for this into Mail?