When new fees for most U.S. Citizenship and Immigration Services (USCIS) forms went into effect on December 23, 2016, the agency published updated versions of the forms. USCIS strongly encourages applicants to submit the new versions, which have an edition date of 12/23/16. However, USCIS said it will accept most prior versions of forms until February 21, 2017, but all filings postmarked December 23 or later must include the new fees or they will be rejected. USCIS said it will accept only the new 12/23/16 edition of Form N-400, Application for Naturalization.