[Dovecot] MUA notifications on new mail in a new folder?

If deliver gets run with a non-root userid like this: < | deliver -m path/to/NEWmaildir >, I wonder, is a connected IMAP MUA automatically notified, that the new message has arrived in the new folder? As I see from some experiments with Thunderbird, it has no problems with immediate notifications of new mail in previously existing folders, however, it has problems with the case of new folder.