Discovery Search and Public Folder mailboxes are not supported.
Dynamic Distribution groups are not supported.
The type property for shared and resource/equipment mailboxes cannot be resolved. Such mailboxes will be available for backup with a general ‘User’ type (Note: This limitation only applies to creating a backup jobs and does not affect licensing).
SharePoint Web Parts can only be backed up if their ‘exportmode’ property is enabled. Non-exportable Web Parts are not supported.
OneNote restore is not supported.
SharePoint Web Part customized template cannot be preserved upon a restore. All Web Parts will be restored with the default template.
The ‘Allow multiple responses’ setting in survey lists within team modern sites is not preserved upon a restore.