Will it be sufficient to have users adjust their calendar manually and just run the exchange tool?

Q: if we choose not to run the the exchange calendar tool against the mailboxes or the Outlook update tool and we just have our users adjust their calendar manually, will that be sufficient? do we still have to run the 926666 update?
A: 926666 is only required if you have applications that use CDO to connect to Exchange such as OWA, Lotus Notes connector, Blackberry, etc. It is recommended that you install the update.