N.Y. Election Law § 10-114
* 1. The board of elections shall cause all military ballots received by it before the close of the polls on election day and all ballots contained in envelopes showing a cancellation mark of the United States postal service or a foreign country's postal service, or showing a dated endorsement of receipt by another agency of the United States government or are signed and dated by the voter and one witness thereto, with a date which is ascertained to be not later than the day of the election and received by such board of elections not later than seven days following the day of a primary election and not later than thirteen days following the day of a general or special election to be cast and counted. * NB Effective until December 31, 2020 * 1. The board of elections shall cause all military ballots received by it before the close of the polls on election day and all ballots contained in envelopes showing a cancellation mark of the United States postal service or a foreign country's postal service, or showing a dated endorsement of receipt by another agency of the United States government or are signed and dated by the voter and one witness thereto, with a date which is ascertained to be not later than the day before election and received by such board of elections not later than seven days following the day of a primary election and not later than thirteen days following the day of a general or special election to be cast and counted. * NB Effective December 31, 2020