Feature request: Support of "Recall this message" in "Outlook" clients

[dev8765]

I'm on the community-repository on openSUSE-Leap-15.5 gromox-2.27.4.g5639431-lp155.21.1.x86_64

The feature "Recall this message" of the Outlook for Windows clients of senders should be fully supported. The below is meant only for those recipient clients where recalls are technically possible, at least for Outlook for Windows/MAPI and OWA.

Implementation might be done in steps:

1. The current sending of new recall messages to all recipients should be stopped
2. Display/send the one calling back a notification instead: "Recall is currently unsupported"
3. Implementation as in Exchange servers

My suggestion is to implement this not as it is claimed by Microsoft to be working, i.e. "only unread mails are deleted". It should be implemented as Exchange is really working (at least in our company):

• The mail of the sender is not deleted, it gets a remark "You tried to recall this message on ..."
• Unread mails of the recipients are deleted instantly
• Read mails of the recipients are deleted too, in any case, but with a delay of some weeks/months. So recipients have a chance to protect read mails from deletion by creating a kind of backup, maybe by forwarding the mail to themself.