we have 2 exchange 2003 servers which have been upgraded from 5.5 few years
ago, we are having some issues with Calendar "plan meeting" task in outlook.
if one sets a plan-meeting in her/his oulook and invites certain users, not
only the invited users will be notified but also few un-invited users will
be notified as well.
thank you for any help on this issue

please note: that one of the un-invited users whos' acount has been deleted
long time ago shows up in the list of the sender.