The Post Office has announced that the new barcode will be required on all mail starting January 2013.

The Intelligent Mail barcode is a 65-bar Postal Service™ barcode used to sort and track letters and flats. It allows mailers to use a single barcode to participate in multiple Postal Service programs simultaneously, expands mailers’ ability to track individual mailpieces, and provides greater mail stream visibility.

Source: https://www.usps.com/election-mail/creating-imb-election-mail-kit.pdf