Updated March 13th: The USPS says these stamps will be issued October 5 in New York, which would coincide with the ASDA stamp show.
From the USPS, November 22nd, 2016:
The 2017 Christmas season will be celebrated with four new Forever stamps featuring images that illustrate four beloved Christmas carols: “Jingle Bells,” “Deck the Halls,” “Silent Night,” and “Jolly Old Saint Nicholas. ” Familiar lines from each song highlight the individual stamps. Shades of blue in the stamp backgrounds evoke the evening scenes from the four carols. This booklet of 20 stamps includes five of each design. The late Howard E. Paine was art director; artist Steve McCracken created the original art.