Folders and groupings of mails can no longer be viewed
In virtual directories mails can be grouped or are marked as read / unread. If the directories are virtual, they are linked to the webmailer and cannot be accessed by other mail clients. The mails should be retrievable in general, but their grouping will be lost on any new mail client.
If you use the email client 'Thunderbird', the own mailbox can be subscribed to show missing folders. In the following dialog all desired folders can then be selected.