21 August 2020
From the USPS announcement on 22 October 2019:
In 2020, the Postal Service issues four new stamps in a booklet of 20 available for notes, cards and letters of thanks sent to acknowledge a favor, an act of kindness, a job well done or gifts sent for any occasion. Highlighted in gold foil are the words “Thank you” in cursive script and an elegant floral design that swirls through and around the words. Each stamp features one of four background colors: blue gray, deep blue, muted green or soft maroon. Greg Breeding was the art director. Dana Tanamachi was the stamp designer and lettering artist.
These stamps will be issued Friday, 21 August 2020 at Hartford, CT, planned site of Great American Stamp Show (American Philatelic Society / American Topical Association / American First Day Cover Society).