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The Year 2007 problem also known as Y2K7 (or DST07) is an error caused by a US-mandated change to Daylight Saving Time, which has repercussions in the computer industry.^[1] Starting in 2007, Daylight Saving Time in many jurisdictions of the United States and Canada began earlier and will run later than in previous years; it started on the second Sunday in March and will end on the first Sunday in November.^[1]

Any device that automatically corrected its clock to match the time changes to Daylight Saving Time, such as personal computers or VCRs now needs to be updated so that the device knows of the new rules.^[1] If the devices are not updated, they show an incorrect time for three weeks in March and one week in November, and cause a number of problems including having e-mail with wrong timestamps, events in calendaring software used on PDAs and other computers being displayed incorrectly or set for the wrong time or synching between devices that are aware of the changes in DST and those that aren't (as between an updated Blackberry or Palm device and a computer either of which may require their own updates) and some authentication software, such as Kerberos in Mac OS not behaving properly.^[1] To avoid these problems users either have to update their devices manually when Daylight Saving Time changes, or update their software to newer versions.

==Equipment affected. The week before the change became effective, Apple Computer informed all online Mac OS X users of a needed update, which was automatically downloaded, installed, and activated aftuer a few mouseclicks. Users who installed the update saw their computers' clocks make the time change at the specified time.

Certain radio clocks, such as Casio Wave Ceptor models, were not able to make the change on the new date without manual intervention. users who were awake at 2 a.m. on the changeover date saw the watch display a symbol indicating that the watch was receiving a time signal, but the tim signal did not make the watch turn on "DST mode". There is a workaround for this, which a diligent user can puzzle out from careful reading of the manual. It requires turning on DNT manually rather than waiting three weeks for to the watch to do it itself. Presumably, the watch will require similar attention oaround the Fall date appointed to r"fall back" to Standard Time. One might ekpect that feture Wave Ceptor watches will contain instructions to switch to and from DST on the new dates automatically. A well-trained consumer will gladly toss a perfectly functional wristwatch into the nearest landfill and rush out to buy the newest model, then pay a jeweler to resize the band and carufully study the manualto learn how to set the local time zone, enable time-signal reception, and synchronize the analog hands with the digital display. These users will also be rewarded to discover that their new watch will follow the latest DST protocol.

Contents 1 Countries Affected and Specific Implementation 1.1 Areas changing in 2007[2] 2 Medical equipment 3 See also 4 References 5 External links

Implications of the changes in Daylight Saving Time extended beyond the United States as neighbouring counties had to decided if they would change their DST rules to remain in step with the United States.

• United States (NOT observed in Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands and the state of Arizona [except the Navajo Native American Reservation, which does observe. Navajo Nation participates in the Daylight Saving Time policy, due to its large size and location in three states.])^[3] Note especially that most of the state of Indiana used to not participate but started in 2007 and most of the state adopted Eastern Time Zone while some counties adopted Central Time Zone.^[4]

• Canada (except most of Saskatchewan, and a few other isolated areas; also, Newfoundland switches at 00:01 rather than 02:00 local time)
• Cuba (switches at 00:00 local time)

Some medical devices and hospital equipment may generate adverse events because of the changes. These could harm patients and not be obvious to clinicians responsible for care. The FDA has published a preliminary public health notification on the subject.

• Daylight saving time
• Year 2000 problem
• Year 2038 problem

• Extended Daylight Saving Time Review and Considerations A Review of the Potential Impact of Daylight Saving Time Changes in 2007 — A Reference for Users and Systems Administrators, Calendaring and Scheduling Consortium for 2007
• 2007 Time Zone Changes Will Impact Many Computers in Canada, the United States and Bermuda
• Are You Prepared for DST 2007? Considerations for 2007 changes
• Daylight Saving Time — The Year 2007 Problem January 11, 2007
• Change in Daylight Saving Time Effective 2007 by Mary Salvas on last edited Feb 28, 2007
• Techies Working To Stay Ahead Of Y2K7 Bug Daylight Saving Change Challenges Computer Programmers, KETV News.
• Daylight Saving Time May Bite the Out-of-Date by Andrew Laurence, 2007-01-29 (followup Daylight Saving Time Saved, by Andrew Laurence 2007-02-19)
• New 2007 Rules for Daylight Savings Time