Description: 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, at 2:00 A.M. on the second Sunday in March. DST will end one week later, at 2:00 A.M. on the first Sunday in November. This update supersedes and replaces update 928388, released in November 2006. This update also includes additional time zone changes that were signed into law after update 928388 was created. Customers who have already deployed update 928388 should evaluate if any of the six specific time zone changes that are addressed in update 931836 merit deploying this update immediately. If systems are not directly affected, you can schedule deployment at the next available opportunity. We recommend that all customers standardize on the most current Windows cumulative time zone update to guarantee the consistency of the time zone database on all systems.

Update type: Important

Release date: June 26, 2007

Applies to: All versions

Knowledge base: support.microsoft.com/kb/931836

Download link: 32-bit | 64-bit

Comments: This update add new information for the following time zones:

• Central Brazilian Standard Time and E. South America Standard Time
  Legal confirmation of 2007 DST laws was not received in time to include in prior cumulative time zone update. This update also sets the correct time to 00:00:00 for both time zones.
• Iran Standard Time
  Legal confirmation that DST is no longer used was not received in time to include in prior cumulative time zone update.
• Namibia
  Correct DST start and end dates from prior cumulative time zone update.
• Newfoundland Standard Time
  Adoption of the U.S. and Canada 2007 DST rules were signed into law after the prior cumulative time zone update was created.
• W. Australia Standard Time
  DST trial period was signed into law after the prior cumulative time zone update was created.