Year 2007 problem

{{Short description|Timekeeping issue in some countries}} The '''year 2007 problem''', also known as '''Y2K7''' (or DST07), was an issue caused by the U.S. Energy Policy Act of 2005, which changed the dates for daylight saving time in the United States, and other national or regional legislation. The change had repercussions in the computer industry.<ref name="tidbits">{{cite web | date = 2007-01-29 | accessdate = 2007-03-01 | title = Daylight Saving Time May Bite the Out-of-Date | publisher = tidbits.com | url = http://db.tidbits.com/article/8832 | first = Andrew | last = Laurence}}</ref> Starting in 2007, daylight saving time in many jurisdictions of the United States and Canada began earlier each year and ran later each fall than in previous years; in 2007, for instance, it started on the second Sunday in March and ended on the first Sunday in November.<ref name="tidbits" /> Preparations in advance of the change prevented major disruptions or incidents,<ref name="Leyden2007-3-12"/> though some isolated glitches were reported affecting, among others, Google AdWords and Microsoft Windows users.<ref name="Leyden2007-03-13">{{cite news |last=Leyden |first=John |date=17 March 2007 |title=Y2K7 bug causes isolated glitches |url=https://www.theregister.com/2007/03/13/y2k7_bug_feedback/ |work=The Register}}</ref>

==Preparation efforts== The legislation regarding daylight savings time had been stable for two decades, so many computers were not designed to be able to handle the change.<ref name="AssociatedPress2007">{{cite news |url=https://redmondmag.com/articles/2007/03/08/lastminute-prep-for-dst-bug.aspx |title=Last-Minute Prep for DST Bug |date=8 March 2007 |work=Redmond |agency=Associated Press}}</ref> The year 2007 problem required updating many computer systems and applications, particularly those relying on time stamping such as scheduling software, e-mail and calendar programs, and automated back-up routines.<ref name="Leyden2007-3-12">{{cite news |last=Leyden |first=John |date=12 March 2007 |title=Y2K7 bug fails to bite |url=https://www.theregister.com/2007/03/12/y2k7_bug/ |work=The Register}}</ref> Preparations required a significant effort by developers and corporate information technologists.<ref>{{cite news |author-first=Steve |author-last=Lohr |title=Time change a 'mini-Y2K' in tech terms |url=https://www.nytimes.com/2007/03/05/technology/05daylight.html |work=The New York Times |date=5 March 2007 |url-access=subscription |access-date=21 February 2017 |archive-date=1 February 2017 |archive-url=https://web.archive.org/web/20170201213854/http://www.nytimes.com/2007/03/05/technology/05daylight.html |url-status=live }}</ref><ref name="Leyden2007-3-12"/> Any device that automatically corrected its clock to match the time changes to daylight saving time, such as personal computers and VCRs, needed to be updated so that the device would know of the new rules.<ref name="tidbits" /> Complex networks which combined older and newer equipment often require manual intervention and required engineers to study how differing computing applications process time.<ref name="AssociatedPress2007"/>

==Problems and anticipated impacts== If the devices weren't updated, they would show an incorrect time for three weeks in March and one week in November, causing a number of problems, including e-mails with wrong timestamps; events in calendaring software used on PDAs and other computers being displayed incorrectly, set for the wrong time, or syncing between devices that are aware of the changes in DST and those that aren't (e.g. between an updated BlackBerry or Palm device and a computer either of which required their own updates); and some authentication software, such as Kerberos in Mac OS X, not behaving properly.<ref name="tidbits" /> To avoid these problems, users either had to correct their devices manually for daylight saving time changes or apply vendor-supplied updates.

===Medical equipment=== It had been warned that the changes could cause some medical devices and hospital equipment to generate adverse events which could harm patients and would not be obvious to clinicians responsible for care. The U.S. Food and Drug Administration (FDA) published a preliminary public health notification on the subject.<ref>{{cite web |url=http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/PatientAlerts/ucm064705.htm |title=FDA Preliminary Public Health Notification: Unpredictable Events in Medical Equipment due to New Daylight Saving Time Change |website=fda.gov |url-status=dead |archive-url=https://web.archive.org/web/20090731115215/https://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/PatientAlerts/ucm064705.htm |archive-date=2009-07-31}}</ref>

==Countries affected== Implications of the changes in daylight saving time extended beyond the United States as neighbouring countries had to decide if they would change their DST rules to remain in step with the United States.

; Areas changed in 2007<ref name="counties">{{cite web |url=https://www.worldtimezone.com/dst_news/dst_news2007.html |title=Time change and DST (Daylight Saving Time) News |website=worldtimezone.com |accessdate=2026-05-22}}</ref> *'''United States''' (Not observed in Hawaii, American Samoa, Guam, Puerto Rico, the Virgin Islands and the state of Arizona [except the Navajo Nation, which observes daylight saving time due to its large size and location in three states.])<ref>{{cite web |url=http://www.daylight-saving-time.com/usa/dst-2007.htm |title=Daylight Saving Time USA — United States of America from 2007 |website=daylight-saving-time.com |url-status=dead |archive-url=https://web.archive.org/web/20060623121317/http://www.daylight-saving-time.com/usa/dst-2007.htm |archive-date=2006-06-23}}</ref>{{unreliable source|date=May 2026}} Note especially that most of the state of Indiana did not observe daylight saving time until 2006, when most of the state adopted Eastern Standard Time.<ref>{{cite web |url=http://wwp.daylight-saving-time.com/usa/indiana/index.htm |title=Indiana and DST |website=daylight-saving-time.com |url-status=dead |archive-url=https://web.archive.org/web/20071207134243/http://wwp.daylight-saving-time.com/usa/indiana/index.htm |archive-date=2007-12-07}}</ref>{{unreliable source|date=May 2026}} *'''Canada''' (except most of Saskatchewan, and a few isolated areas; also, Newfoundland switches at 00:01 rather than 02:00 local time) *'''Cuba''' (switched at 00:00 local time) *'''New Zealand''' extended daylight saving times starting in the last Sunday in September (instead of the first Sunday in October) *'''Argentina''' introduced daylight saving time in 2007 for most but not all of the country.

==References== {{reflist}}

==External links== *[http://www.calconnect.org/dstlinks.shtml 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 *[https://wiki.brown.edu/confluence/display/CISDOC/Daylight+Saving+Time+(DST)+Updates Change in Daylight Saving Time Effective 2007] by Mary Salvas on last edited 28 February 2007

2007 Category:2007