Update Your Exchange Organization When Daylight Saving Time or the Time Zone Changes

Applies to: Exchange Server 2010 SP3

Topic Last Modified: 2011-11-01

If the country or region where your organization or some of your users reside has changed their policy of recognizing Daylight Saving Time (DST), or changed the local time offset from Coordinated Universal Time (UTC), you need may need to update Microsoft Windows, Microsoft Exchange, Microsoft Outlook, or other programs to accommodate these changes.

For more information about DST changes around the world, including links, see the Microsoft Daylight Saving Time Help and Support Center. To find out if there are current DST or time zone issues, see the Office 365 release notes. Also visit the support Web sites of your other software suppliers to see if they require any additional updates.

Even if your time zone hasn't changed, if you interact with other computers or users globally, your computer needs to be able to perform accurate date and time calculations for events elsewhere in the world.

Installing time zone updates as soon as possible minimizes the number of meetings or appointments that are scheduled during the transition from the old time and date to the new one.

Step 1: Install the Windows DST update on all client and desktop computers

Because the Office 365 authentication system is updated when DST or a time zone changes, all Office 365 client computers need to be updated or they may experience connectivity issues.

Make sure all client and desktop computers have installed the Windows DST update. For more information, see How to configure daylight saving time for Microsoft Windows operating systems.

Step 2: Install the Windows DST update on all servers

Update all your on-premises servers with the Windows DST update.
If you’re running Office 365, update any servers that interact with the Office 365 authentication system, such as DirSync or AD FS servers. These servers must be updated to ensure uptime.

Note If you’re updating server clusters, make sure you follow the usual process for updating clusters. You update the passive server first, fail over to the passive server (which becomes active), and then update the formerly active (now passive) server. For more information about how to update server clusters and high-availability server clusters, see Update Exchange Server Clusters and High Availability Servers.

Step 3: Update Exchange 2003 SP2 and Exchange 2007 SP3 servers with the latest updates

Install the latest DST update on your Exchange servers. For more information, see CDO time zone tables.

Step 4: Update Exchange and Outlook on all client and desktop computers

Determine which of your users need to run the Exchange or Outlook time zone tools, and which tool to run, using the table following this procedure.
Send a message to your users who need to update their computers, giving them a link to the appropriate tool.

The following table shows when users should run the Exchange Calendar Update Tool or the Time Zone Data Update Tool for Microsoft Office Outlook. Find which version your organization’s servers are running, and then determine which client programs your users are running.

	Client Version
Organization version	Outlook 2003	Outlook 2007	Outlook 2010
Exchange 2003 on premises	Exchange Calendar Tool or Time Zone Data Update Tool for Microsoft Office Outlook	Exchange Calendar Tool or Time Zone Data Update Tool for Microsoft Office Outlook	No action required
Exchange 2007 on premises	Exchange Calendar Tool or Time Zone Data Update Tool for Microsoft Office Outlook	Exchange Calendar Tool or Time Zone Data Update Tool for Microsoft Office Outlook	No action required
Exchange 2010 on premises	Time Zone Data Update Tool for Microsoft Office Outlook	Time Zone Data Update Tool for Microsoft Office Outlook	No action required
BPOS-S (Exchange 2007)	Time Zone Data Update Tool for Microsoft Office Outlook	Time Zone Data Update Tool for Microsoft Office Outlook	No action required
BPOS-D (Exchange 2010)	Time Zone Data Update Tool for Microsoft Office Outlook	Time Zone Data Update Tool for Microsoft Office Outlook	No action required
Office 365 (Exchange 2010)	Not supported	Time Zone Data Update Tool for Microsoft Office Outlook	No action required