I still have to edit my database with builders related modification (changeset 13996 - movable/clonable items)... Everything seems like to work well :-) (I am not using all features).

IMHO this is no acceptable reason to wait longer for a decent Mailbox Outbox :-( (Account owner beeing shown as Author for all sent messages rather than showing the Recipients of the messages)... After all, this is a really basic feature; historically the first functionnality of Internet !!!