I'm watching for this year's update. This info was posted here last year -
Apple's website says most products and accessories purchased in store (or received if ordered online) between November 15, 2017 and December 25, 2017 will be eligible for return until January 8, 2018 in the United States, Canada, Australia, United Kingdom, Germany, France, Netherlands, Sweden, and select other regions.
The dates are slightly different in a few countries, including Italy, Japan, and Spain, where most products and accessories purchased between November 15, 2017 and January 6, 2018 will be eligible for return until January 20, 2018.