Intelligent Mail barcode (IMb) is mandatory starting January 2013 for all automated pieces.  The reason the USPS changed the requirements is to help reduce or eliminate manual processes. You will need to use them on all letters, flats, postcards, Business Reply Mail and Permit Reply Mail or you won’t receive the full automated discounts. The barcode holds all routing, sorting and additional services information on the envelopes. Remember if you are reprinting a BRM don’t just send it to print.  It will need to be updated through the USPS in order to get processed. Just in case you overlook it will update it for you.

USPS requirements for IMb