Attendee availabilty not updating
 

I've been searching for a solution or explanation for this issue which I'm
sure is a known one, nonetheless I hope someone can help....

OK we have users who are on outlook 2000 (SP3) with their pop3 accounts, and
a small percentage of users on Exchange 2003 using Outlook 2003 (SP2).

If the user on O2K sends out a meeting request and a user on O2K3 responds,
the sender's (O2K) calendar/attendee availability is not updated.

Is there any way to resolve this other than upgrading the user to O2k3
and/or Exchange?