/etc/zarafa/archiver.cfg:

archive_enable          = yes
archive_after           = 0
track_history           = yes
cleanup_action          = store
enable_auto_attach      = yes

Setting archive_enable = yes and archive_after = 0 causes the archive to archive every new message and every change on each run of the archiver.

The track_history = yes setting causes the archiver to not update the archived copies of messages that were altered after they were archived but to make a new archived copy and move the old copy to another special folder in the users archive: Zarafa Archive/History.

The cleanup_action = store setting changes the behavior of the cleanup operation. Instead of deleting archived copies from the archive when the primary message they reference is deleted, zarafa-archiver will move the archived copy to yet another special folder: Zarafa Archive/Deleted.

The auto_attach_writable = no setting makes sure that the users don’t get write privileges on their archives. If they would have write privileges they could alter or delete messages from their archive, making the history useless.