The Energy Policy Act of 2005 changed the dates for Daylight Saving Time in the U.S. Beginning in 2007, DST will begin the second Sunday in March and end the first Sunday in November: March 11, and November 4, in 2007.
Different layers of computer applications implement DST in different ways. There may be required patching at the OS, database, programming language, or application level to ensure correct representation of current time during the expanded portion of DST as well as correct date calculations that cross the new DST boundaries.
For more detailed information about desktop machines and PDAs please visit the page below.