Exchange and Daylight Saving Time 2007
19.01.2007
As many of you know, there will be a change next year in the transition dates for US daylight saving time. I won't go into all the gory details here, but if you want them follow this link http://www.microsoft.com/windows/timezone/dst2007.mspx This site will be updated to provide all the latest information about daylight saving time, including updates from Microsoft products affected by daylight saving time, as well as links to KB articles when they are available.
The Exchange team, along with Windows and Office have been giving this a lot of attention. We will be providing, free of charge, a solution for Exchange products in mainstream support. This solution will consist of changes in CDO to support these new dates as well as rebasing tool for calendar items that are already existent in users calendars. This rebasing tool is a server side tool. There will also be a client side tool available from Outlook. For products that are no longer under Mainstream support, these non-security updates will only be offered to customers that have an Extended Hotfix Agreement. For more information on the current support status of your Microsoft products and the Support Lifecycle Policy, please visit http://support.microsoft.com/lifecycle.
Why this
In August of 2005 the United States Congress passed the Energy Policy Act, which changes the dates of both the start and end of daylight saving time (DST). When this law goes into effect in 2007, DST 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) than what had traditionally occurred. Microsoft is committed to working with customers to make this transition as seamless as possible for customers affected by these new time changes. We are further committed to working with others in the industry to address the broader challenges presented by this U.S. statute.
While the change in daylight saving time applies to U.S. and Canada, the change may impact customers based outside North America. 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.
What to do if you have an older system
For windows 2000 you can look at You can look at kb:914387
Time zone information is stored here:
Windows XP/2000/NT: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows
NT\CurrentVersion\Time Zones
Windows 9x:
HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Time Zones
In theory, all you should need to do is apply the MS patch to an XP or
2k3 system, export the above registry key and all subkeys and values, and then import it into Windows 2000. I know that Windows 2000 uses the same time zone formats as XP and 2k3. I do not know if NT or Windows 98 do, so beware.
In reality, all you need is the data for the TZI binary value that maps the changeover dates, and practically speaking you only need the time zone the PC lives in.
If you live in the Eastern Time Zone, for example, simply extract:
Key: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows
NT\CurrentVersion\Time Zones\Eastern Standard Time
Value: TZI
You could then use ORCA, WISE, or some similar tool to package the registry changes in an .msi for deployment.
You could also use this:
http://support.microsoft.com/kb/221542
Although that's decidedly the hard way.
Registry changes
The best I can say is
the patch modifies the following Timezones
on my local XP SP2 system:
Alaskan
Standard Time
Atlantic
Standard Time
Central
Brazillian Standard Time
Central
Standard Time
E. South
American Standard Time
Eastern
Standard Time
Israel
Standard Time
Mountain
Standard Time
Pacific
Standard Time
All these keys
have an added key 'Dynamic DST' added to
them, and can be found @
HKLM\Software\Microsoft\Windows NT\Current
Version\Time Zones
Related information
