In the article "DMM Revision: Labeling Trays and Sacks of First-Class Mail" in Postal Bulletin 22195 (12-7-06, pages 10-12), we announced a change in labeling for mixed area distribution center (ADC) and mixed automated area distribution center (AADC) containers of First-Class Mail items, with a required use date of February 18, 2007. We are extending the required use date to March 18, 2007, to allow software vendors more time to incorporate the changes. We still encourage mailers to make the labeling changes as soon as possible. In addition, we revise 705.9.0 of the Mailing Standards of the United States Postal Service, Domestic Mail Manual (DMM) to replace labeling list L002 with labeling list L201 for labeling mixed ADC trays of First-Class Mail consisting of cotrayed presorted and automation-rate flats.  Again we encourage mailers to use the new labeling immediately, but mailers must label containers of First-Class Mail letters, flats, and parcels according to the new standards no later than March 18, 2007.