Older version dont support this, period. Unless you work for Microsoft and can release an update for that specific version of Outlook, there's nothing you can do here :)
Actionable messages in "Microsoft office professional plus 2016"
I have a scenario, where a user receives a mail, from the mail, the user can click on Approve or reject buttons, which internally calls our web server. I'm trying to implement this feature in the "Microsoft office professional plus 2016" desktop app. But this is available in the latest versions only. But I have to solve this for the "Microsoft office professional plus 2016". Please provide me any information to implement this feature.