Came Across Mail Archiving - it seems like only the admin is able to lookup archived mails Why would the user not be able to look up it's own archive? See Mailstore - there the user can lookup his own archive and all archives he has permission to. now the problem there is it requires an outlook addin or a standalone client to do so. On mobile clients it gets messy > pretty sure smartermail could solve this in an integrated way on all platforms.

Also an API should be able to get mails from archive according to filter params.