Exchange accounts offer a “Retention Period” during which you can recover deleted items (mail, contact, calendar entry, task), even though you have emptied the “Deleted Items” folder.
For details see: Change how long permanently deleted items are kept for an Exchange Online mailbox in Exchange Online | Microsoft Learn
eM-Client does not seem to support that (unless I missed something), Outlook (MS Office) does.
So when I delete items in eMClient and then empty the “Deleted Items” folder, they are gone forever.
When I delete items in Outlook and then empty the “Deleted Items” folder, I can still recover them for 30 days.
I think this is a useful feature offered with Exchange accounts.
Are there plans to implement it?