The USPS published its final rule on International Mail changes that will take effect January 21, 2018. The biggest change will be that First-Class International Mail and and Flats can only contain non-dutiable documents. All other matter is classified as goods and is prohibited from being mailed as First-Class International Mail.
From the USPS Federal Register Notice:
123.631 Explanation of Separation
Letter-post mail (First-Class Mail International, IPA and ISAL items, and First-Class Package International Service) must be separated based on contents into Documents and merchandise categories. Merchandise consists of items other than documents that are considered potentially dutiable, as well as documents that may be subject to customs duties. Mailers must declare a value and place a customs form on each merchandise item. If any item (merchandise or document) weighs more than 16 ounces, a mailer must place a customs form on it, regardless of the content.
In Exhibit 123.61 (above), the “Type of Item” column has several references to “documents.” For this purpose, “documents” refers only to any piece of written, drawn, or printed information, excluding objects of merchandise. Documents do not include digital and electronic storage media or devices such as CDs, DVDs, or flash drives. Examples of documents include the following:
a. Audit and business records.
b. Personal correspondence.
f. Written instruments not intended to be resold.
g. Money orders, checks, and similar items that cannot be negotiated or converted into cash without forgery.
123.633 Customs Forms Required
The following are examples of items that are required to bear a customs declaration form and to declare a value:
a. CDs, DVDs, flash drives, video and cassette tapes, and other digital and electronic storage media–regardless of whether they are blank or contain electronic documents or other prerecorded media.
c. Collector or antique document items.
f. Printed music.
g. Printed educational or test material.
h. Player piano rolls.
i. Commercial engineering drawings.
j. Commercial blueprints.
n. Separation negatives.
o. Commercial photographs.
141.5 First-Class Mail International
[Revise the first two sentences to read as follows:] First-Class Mail International is a generic term for mailpieces that are postcard size, letter-size or flat-size and weigh 4 pounds or less. First-Class Mail International items may contain any letter-size or flat-size mailable correspondence or nondutiable documents that are not prohibited by the destination country. * * *
141.6 First-Class Package International Service
[Revise the second sentence to replace “registry” with “Registered Mail,” to read as follows:] At the sender’s option, extra services, such as Registered Mail and return receipt, may be added on a country-specific basis.* * * * *
240 First-Class Mail International
242.1 Content Eligibility
[Revise text to read as follows (indicating that only correspondence and nondutiable documents may be sent by FCMI)]: Subject to applicable weight and size limits, only correspondence and nondutiable documents that are otherwise acceptable and not prohibited by the Postal Service or the country of destination may be mailed at the First-Class Mail International price.
[Revise the heading of 242.2 to read as follows:]
[Replace subsections 242.21 and 242.22 with text to read as follows (because no merchandise, neither dutiable as in the previous 242.21 nor nondutiable as in the previous 242.22, may be mailed with First-Class Mail International service):] No merchandise, whether dutiable or nondutiable, may be mailed using First-Class Mail International Service. Items containing merchandise may be sent by Global Express Guaranteed service, Priority Mail Express International service, Priority Mail International service, or First-Class Package International Service; commercial mailers may also use IPA packages (small packets) and ISAL packages (small packets).