add awareness of missing folders (#2578)

## Does this PR need a docs update or release note?

- [x] ✅ Yes, it's included

## Type of change

- [x] 🗺️ Documentation
## Issue(s)

* #2567

CHANGELOG.md

@@ -10,6 +10,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - Show owner information when doing backup list in json format
 
+### Known Issues
+- Folders and Calendars containing zero items or subfolders are not included in the backup.
+
 ## [v0.4.0] (alpha) - 2023-2-20
 
 ### Fixed

website/docs/support/known-issues.md

@@ -14,6 +14,9 @@ Below is a list of known Corso issues and limitations:
 
 * Restoration of Nested attachments within Exchange Mail or Calendars aren't yet supported.
 
+* Folders and Calendars containing zero items or subfolders aren't included in the backup.
+
 * Provides no guarantees about whether data moved, added, or deleted in M365
   while a backup is being created will be included in the running backup.
   Future backups run when the data isn't modified will include the data.
+