The referenced article also has plenty of mistakes. :laugh:
Ask Ars: Why will Apple's Do Not Disturb bug fix itself next week?
For example:
"The first day of 2013 started on a Tuesday, whereas (as noted by TUAW) the ISO standard expects the first week of the year to start on "the Monday that contains the first Thursday in January." In this case, that would be January 7, 2013."
The first ISO week for 2013 starts on December 31, 2012, not January 7, 2013. The first ISO week of the year can start no later that January 4 of any year, and will be in the range of 29 December of the prior calendar year to 4 January of the current calendar year.
ISO week date