You could use the ICS (Incremental Change Synchronization) API for that, but
it is only available in Extended MAPI.

Dmitry Streblechenko (MVP)
http://www.dimastr.com/
OutlookSpy - Outlook, CDO
and MAPI Developer Tool

"Tadwick" wrote in message
...
Hi there,

If I write some code that returns all appointments for Exchange users that
have delegated reveiw permissions to me, how should I cache the info so
that I only need to return appointment data that has been modified since
the last time I checked? I understand how to filter out older, unchanged
data but I'm wondering if there is a way that outlook cache's the older
data and for how long? Alternatively, could I store that user's data in a
local calendar folder or do I need to write it to a database or other
local data store?

Assume Windows XP/Outlook 2003/Exchange 2003.

Thanks