Microsoft will not supply free Daylight Saving Time (DST) 2007 patches to update Exchange Server 5.5 and Exchange 2000. Enterprises relying on these systems must evaluate their exposure and take action now.

Scope of the DST 2007 Problem for Exchange

The new United States and Canada DST adds four weeks to the previous DST period, beginning on the second Sunday in March and ending on the first Sunday in November. Software that is not updated will fail to switch to DST and remain out-of-sync by one-hour for those four weeks. For links to vendor patches and a plan to tackle DST 2007 preparations, refer to the Info-Tech Advisor research note, "Save the Day: Prepare for Daylight Saving Time 2007."

For all Exchange products, an additional problem originates within the Collaboration Data Object (CDO), which uses a proprietary internal calendar to determine when DST starts and stops (see sidebar). This does not affect normal Outlook appointments generated from PCs running Outlook within properly patched operating...p>