On March 26, 2016, the USCIS published a revised version of the Form N-400, Application for Naturalization. The edition is dated 03/26/16. In a response to an inquiry from AILA, the USCIS explained that applicants for naturalization may continue to use the older edition that is dated 09/13/13 until December 1, 2016.
See AILA Doc. No. 16092931