High Priority Product Alert: Daylight Saving Time changes for the U.S. and Canada in 2007

We would like to bring this important high product alert to your attention.  Please share this information with your internal staff and customers as appropriate.




One of the key provisions of the Energy Policy Act of 2005 was to extend Daylight Saving Time (DST) by approximately four weeks. In compliance with this provision, beginning in 2007  DST dates in the United States will start three weeks earlier (2:00 A.M. on the second Sunday in March) and will end one week later (2:00 A.M. on the first Sunday in November).


Microsoft is committed to making this transition as seamless as possible for our users affected by the new Daylight Saving Time changes. As a service to customers, Microsoft will be producing an update for Windows products as well as other Microsoft products affected by the new U.S. statute. These updates will be released through technical support channels including Microsoft Customer Support Services (CSS), as well as online channels such as Windows Update and Microsoft Update. 


Details of the updates for Microsoft Windows and affected Microsoft applications, how customers can acquire them and when they will be available can be found on the Microsoft website at http://www.microsoft.com/windows/timezone/dst2007.mspx.  Corresponding Technical Knowledge Base Articles can be linked to from this website as well.


Microsoft is providing the Time Zone updates at no-cost for customers on Windows platforms that are covered by mainstream support.  Customers who have an Extended Hotfix Support Agreement can request a hotfix for products in Extended Support.  For more information on the current support status of your Microsoft products and the Support Lifecycle Policy, please visit http://support.microsoft.com/lifecycle.”


Additional Details


This is a High Priority Product Alert, regarding the preparations for the Daylight Saving Time changes in March 2007 in the United States due to the Energy Policy Act of 2005.  This update is being shared to help enterprise customers as Microsoft will be producing various updates for Microsoft products affected by the new United States daylight saving time transition dates.


Areas Affected:

·         U.S.

·         Canada

·         Mexico*

·         All other Areas/Subs who have Companies or organizations with operations, customers or vendors based in North America may be affected. In addition customers who interact or integrate with systems that are based in North America or rely on date/time calculations may be impacted.


*Please note that Mexico will not be following the new DST 2007 rules with the U.S. and Canada. Accordingly such systems configured to use U.S. time zones (for example, Pacific Time) will need to change their system configurations to use the new Mexico time zones.


In general, computer systems should be updated to reflect the new DST rules. For most customers, this means applying software updates to select Microsoft products, including various releases of the Microsoft Windows servers and operating systems, Microsoft Office and other applications. In a few important cases, customers must take more considered action, as outlined below.




Starting in the spring of 2007, daylight saving time (DST) start and end dates for the United States will transition to comply with the Energy Policy Act of 2005. DST dates in the United States will start three weeks earlier (2:00 A.M. on the second Sunday in March) and will end one week later (2:00 A.M. on the first Sunday in November). This will impact international customers and partners who transact business with companies in the US.




Impacted Dates for 2007 (please note: dates may change in future years):



Previous DST Start


New DST Start


Previous DST End


New DST End



First Sunday of April


Second Sunday of March


Last Sunday of October


First Sunday of November



April 1st, 2007


March 11th, 2007


October 28th, 2007


November 4th,2007



The change in DST will have an impact on many automated and technology reliant products. Individual consumers, small to medium size businesses and large enterprises may be impacted by the new change in time. In many cases, making the necessary changes to accommodate the new DST legislation will be a relatively minor task. Users may need to manually adjust the time on their devices when the change occurs.


In other cases, more substantial efforts may be required. In some cases, systems and applications may need to be updated directly, while in others, the application may simply inherit or "read" the date and time information from the underlying system that it resides on so the changes need only be made to that underlying system. Given the broad range of technology in use today—and the integration of systems between customers, vendors, and partners—business and IT managers should determine what actions should be taken to mitigate the impact of DST 2007 on their organizations.


Microsoft is producing updates for Microsoft products affected by the new United States daylight saving time transition dates. These updates will be released through a combination of channels including Microsoft Customer Support Services (CSS), hotfixes incorporated in Knowledge Base articles, Windows Update, Microsoft Update, Windows Server Update Services (WSUS), and the Microsoft Download Center.


Will there be additional messaging regarding the DST product updates?


·         This information is being communicated internally in the externally via the DST page on the Microsoft.com website (http://www.microsoft.com/windows/timezone/dst2007.mspx) and various product group blogs. 


·         Additional Field Bulletins and Advisories may be updated for any new available product updates as available.



If you need further information or clarification from Microsoft, please contact your Technical Account Manager, Application Development Consultant or your MS Account Team.

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