Postcom.org posted the following DMM Advisory Update: Upcoming DMM Change: Attachments on Letter-size Mail. An upcoming change in the December 6 update of the Domestic Mail Manual will allow attachments on letter-size mail when postage is paid at automation letter prices. The revision, which will be published shortly, provides the physical characteristics and preparation methods for perforated pockets with edges that are permanently affixed to a letter-size mailpiece. In short, a pocket is formed within a two-ply unit and sales offers, coupons, and similar printed advertising may be placed within or underneath the pocket. The perforated panel must be lifted to reveal the material inside. Perforated pockets may be applied to Standard Mail and Periodicals letter-sized mail and cannot contain personal information. Note that perforated pockets are not considered sealed against postal inspection.