Brookings: On December 24, 2025, a quiet change took effect in the Postal Service’s Domestic Mail Manual. The new section (DMM 608.11) now clarifies that a postmark will no longer indicate the date a piece of mail was deposited with U.S. Postal Service (USPS). The Postal Service notes this misalignment “has and will become more common” as it continues consolidating its processing network and standardizing transportation schedules under the Delivering for America (DFA) plan.
Although the rule is technical, its implications reach well beyond postal operations. For more than 70 years, legal and administrative systems have treated a postmark as reliable evidence of when an individual met a deadline: when a ballot was mailed, when a tax return was filed, when a court document was submitted, or when an application was received. This reliance made sense in a network where most mail entered processing close to where it was deposited, keeping the postmark closely aligned with the date of mailing.
