I am running WP on the Nokia Lumia 1020. Previously I had multiple Outlook email subfolders pinned to my homescreen, and whenever one received an email I would get a sound notification. I recently upgraded to 8.1 and this is gone: new emails to subfolders update the tile but don't notify me. I cannot seem to find a setting to restore the old behaviour. Has this been removed, or is there a way to restore it?
Unfortunately at the moment there is no option to turn on notifications on email subfolders. You should consider voting for this issue on https://windowsphone.uservoice.com/forums/101801-feature-suggestions/suggestions/2486216-new-email-notification-for-sub-folders
