In new Scalix 11 ( 11.0.0, 11.0.1 and 11.0.2 ) when one uses any of: imapsync, imapcopy and others -- the message read flag is copied, but Outlook and IMAP clients shows every message as new !!!
WIth the same version of imapsync, imapcopy and others and Scalix 10.0.X - there is no such problem !