Currently there is no way to recover a previous version of an edited or deleted discussion post. This can be a problem as a student caught in a situation of questionable academic integrity can edit or delete the evidence. For graded discussions this can also create accreditation issues because the grading artifact can be altered.

While the simple answer is 'disallow edits and deletes', these do have value. Double-posts can be cleaned up directly by the student, minor typos can be corrected, and the vast majority of students and faculty benefit from allowing edits.

If discussions had versioning that was available to the faculty, so the multiple versions of a post could be viewed, this would eliminate the downsides of allowing edits while retaining all the benefits.