 New delivery standards were issued in January 2015, and the majority of single-piece (not presorted) first-class mail is now being delivered in two days instead of one.Large commercial mailers can still have first-class mail delivered overnight if delivered directly to a processing center in the early morning, though as of 2014 this represented only 11% of first-class mail.Unsorted first-class mail will continue to be delivered anywhere in the contiguous United States within three days.