Prepare for a change to your time zone

 

If the country or region where your organization or some of your users reside has changed its policy of recognizing daylight saving time (DST), or changed the local time offset from Coordinated Universal Time (UTC), you may need to update Windows, Microsoft Exchange, Microsoft Outlook, or other programs that you use with Microsoft Office 365 for professionals and small businesses to accommodate these changes.

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

Installing the time zone updates as soon as possible minimizes the number of Outlook and Exchange meetings or calendar events that are scheduled during the transition from the old to the new time and dates.

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

Make sure all client computers have installed the Windows DST update. For more information, see How to configure daylight saving time for Microsoft Windows operating systems. Consult the release notes for current issues relating to time zones.

Because the Office 365 authentication system will be updated, all Office 365 client computers need to be updated or they may experience connectivity issues.

Step 2: Install the Windows DST update on all servers

Update all of your on-premises servers with the Windows DST update. If you are running Office 365, any servers that interact with the Office 365 authentication system, such as Azure Active Directory Sync tool or Active Directory Federation Services (AD FS) 2.0, must be updated to ensure uptime.

If you are 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 on updating server clusters and high-availability server clusters, see Updating cluster 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.

If you are updating server clusters, again make sure you follow the usual process for updating clusters. See Updating cluster and high-availability servers.

Step 4: Update Exchange and/or Outlook on all client computers

Check whether and which of your users need to run the Exchange or Outlook time zone tools, and which tool to run.

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

Organization Version	Client Version
	Microsoft Office Outlook 2003	Microsoft Office Outlook 2007	Microsoft 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 Standard (Exchange 2007)	Time Zone Data Update Tool for Microsoft Office Outlook	Time Zone Data Update Tool for Microsoft Office Outlook	No action required
BPOS Dedicated (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