We had an instructor delete a conversation/Inbox message with a student then realize that night that the conversation included other messages that she wanted back. She reached out to me as an administrator to try to retrieve the message, but this lead to me realizing (we're new to Canvas) that there is no way for instructors or admins to retrieve deleted conversations.
I found online that Instructure may be able to retrieve deleted conversations, but when I submitted a ticket I was told this is not usually the case and only done for extreme circumstances. It would be beneficial for admins at least, if not other users, to be able to recover messages at least for a time period.
Many email clients have a "deleted items" or "trash" folder to hold deleted messages, that can either be manually deleted permanently or automatically does so every so often. A version of this, or maybe a feature under Admin Tools to restore messages, would be beneficial.