Sorry if old.
http://news.cnet.com/8301-10797_3-57611467-235/xbox-one-practically-unusable-without-day-one-update/
According to one of Microsoft's Xbox team members, Xbox One owners will "need the Day One update" to get going on the upcoming console.
Speaking to Engadget in an interview published on Friday, Microsoft's senior director of product management Albert Penello said that Xbox One owners "will be able to do very little without taking the day one update." When pressed on what users could do with the Xbox One before the update is added to the console, Penello said "nothing."
http://news.cnet.com/8301-10797_3-57611467-235/xbox-one-practically-unusable-without-day-one-update/