The Scott catalogue number for this stamp is 5300.
Updated May 10th: This stamp will be issued July 27th with a listed first-day city of Kansas City, MO. We are not sure if there will be a first-day ceremony.
Original announcement:
With this stamp, the Postal Service pays tribute to the sacrifice of American soldiers and millions of supporters on the home front who experienced World War I. Entering World War I (1914–1918) in its later stages, the United States helped turn the tide of war in favor of the Allies.
Updated June 22nd:
On July 27, 2018, in Kansas City, MO, the U.S. Postal Service® will issue the World War I: Turning the Tide stamp (Forever® priced at the First-Class Mail® rate) in one design, in a pressure-sensitive adhesive pane of 20 stamps (Item 477400). The stamp will go on sale nationwide July 27, 2018.
With this stamp, the Postal Service™ pays tribute to the sacrifice of American soldiers and millions of supporters on the home front who experienced World War I. Entering World War I (1914–1918) in its later stages, the United States helped turn the tide of war in favor of the Allies. The stamp art features a close-up of a member of the American Expeditionary Force holding the U.S. flag. Barbed wire can be seen in the background, as well as an airplane in flight and smoke rising up from the battlefield. The artwork was painted in airbrush on illustration board, a technique that evokes the propaganda posters used during World War I. Art director Greg Breeding designed the stamp with art by Mark Stutzman.
Availability to Post Offices: Item 477400, World War I: Turning the Tide (Forever priced at the First-Class Mail rate) Commemorative Pane of 20 Stamps. Stamp Fulfillment Services will make an automatic push distribution to Post Offices™ with a quantity to cover approximately 30 days of sales.
How to Order the First-Day-of-Issue Postmark:
Customers have 120 days to obtain the first-day-of-issue postmark by mail. They may purchase new stamps at their local Post Office or at The Postal Store® website at usps.com/shop. They must affix the stamps to envelopes of their choice, address the envelopes (to themselves or others), and place them in a larger envelope addressed to:
FDOI – WWI: Turning the Tide Stamp
USPS Stamp Fulfillment Services
8300 NE Underground Drive, Suite 300
Kansas City, MO 64144-9900
After applying the first-day-of-issue postmark, the Postal Service will return the envelopes through the mail. There is no charge for the postmark up to a quantity of 50. There is a 5-cent charge for each additional postmark over 50. All orders must be postmarked by November 27, 2018.
Technical Specifications:
Issue: World War I: Turning the Tide Stamp
Item Number: 477400
Denomination & Type of Issue: First-Class Mail Forever
Format: Pane of 20 (1 design)
Series: N/A
Issue Date & City: July 27, 2018, Kansas City, MO 64108
Art Director: Greg Breeding, Charlottesville, VA
Designer: Greg Breeding, Charlottesville, VA
Typographer: Greg Breeding, Charlottesville, VA
Artist: Mark Stutzman, Mountain Lake Park, MD
Modeler: Joseph Sheeran
Manufacturing Process: Offset, Microprint
Printer: Ashton Potter (USA) Ltd. (APU)
Printed at: Williamsville, NY
Press Type: Muller A76
Stamps per Pane: 20
Print Quantity: 20,000,000 stamps
Paper Type: Nonphosphored Type III, Block Tag
Adhesive Type: Pressure-sensitive
Processed at: Ashton Potter (USA) Ltd. (APU)
Colors: Black, Cyan, Magenta, Yellow, PMS 5473c Blue, PMS 1795c Red, PMS 4505c Gold
Stamp Orientation: Vertical
Image Area (w x h): 0.84 x 1.42 in./21.34 x 36.07 mm
Overall Size (w x h): 0.98 x 1.56 in./24.89 x 39.62 mm
Full Pane Size (w x h): 5.92 x 7.88 in./150.37 x 200.15 mm
Press Sheet Size (w x h): 11.84 x 23.89 in./300.74 x 606.81 mm
Plate Size: 240 stamps per revolution
Plate Numbers: “P” followed by seven (7) digits
Marginal Markings:
Front: Plate number in two corners • Header: World War I – Turning the Tide
Back: ©2017 USPS • USPS Logo • Two barcodes (477400) • Plate Position Diagram • Promotional Text
Updated July 31:
[press release]
World War I: Turning the Tide Forever Stamp
Honoring Those Who Served in Seminal Conflict
KANSAS CITY — Post Offices across the nation are selling the newest stamps to honor the millions of Americans, both home and abroad, who participated in World War I, considered the seminal conflict of the 20th century. World War I: Turning the Tide Forever stamps were dedicated in a special ceremony today at the National World War I Museum and Memorial in Kansas City, MO.
“Even though the United States didn’t see action until the last year of the war, in 1918, American troops played an indispensable role in turning the tide of that war in favor of the Allies,” said dedicating official U.S. Postal Service General Counsel and Executive VP Thomas Marshall. “Today we pay tribute to the sacrifice of those soldiers, as well as the millions of supporters on the home front.”
World War I was a four-year global conflict (1914-1918) that reshaped the map of Europe. The United States remained neutral until April 1917, when it declared war on Germany and entered on the side of the Allies — Britain, France, and Russia. When the American Expeditionary Force, which ultimately grew to nearly 5 million troops, did finally engage in 1918, its actions helped end the war, thrusting the U.S. to the forefront of major world powers.
The stamp art features a close-up of a member of the American Expeditionary Force holding the U.S. flag. Barbed wire can be seen in the background, as well as an airplane in flight and smoke rising up from the battlefield. The artwork was painted in airbrush on illustration board, a technique that evokes the propaganda posters used during World War I. Art director Greg Breeding designed the issuance with art by Mark Stutzman. News of the stamps is being shared using the hashtag #WorldWarIStamp.
Customers may purchase the WWI: Turning the Tide Forever stamps through the Postal Store atusps.com/shop, by calling 800-STAMP24 (800-782-6724) and at Post Office locations nationwide.
Ordering First-Day-of-Issue Postmarks
Customers have 120 days to obtain first-day-of-issue postmarks by mail. They may purchase new stamps at local Post Office facilities, at the Postal Store usps.com/shop or by phone at 800-STAMP-24. They must affix the stamps to envelopes of their choice, address the envelopes to themselves or others and place them in envelopes addressed to:
FDOI – World War I: Turning the Tide Forever Stamps
USPS Stamp Fulfillment Services
8300 NE Underground Drive, Suite 300
Kansas City, MO 64144-9900
After applying the first-day-of-issue postmark, the Postal Service will return the envelopes through the mail. There is no charge for postmarks up to a quantity of 50. For more than 50, customers are charged 5 cents each. All orders must be postmarked by Nov. 27, 2018.
Ordering First-Day Covers
The Postal Service also offers first-day covers for new stamps and stationery items postmarked with the official first-day-of-issue cancellation. Each item has an individual item number and is offered in the USA Philatelic Publication and online at usps.com/shop. Customers may register to receive a free USA Philatelic Publication online at usps.com/philatelic .
Philatelic Products
Philatelic products for this stamp issue are as follows:
477406, Press Sheet, $60.
477410, Digital Color Keepsake, $11.95.
477416, First-Day Cover, $0.94.
477421, Digital Color Postmark, $1.65.
On July 4, 2018, in Colorado Springs, CO, the U.S. Postal Service will issue the O Beautiful stamps (Forever priced at the First-Class Mail rate) in 20 designs, in a pressure-sensitive adhesive pane of 20 stamps (Item 565300). The stamps will go on sale nationwide July 4, 2018.
Availability to Post Offices: Item 565300, O Beautiful (Forever Priced at the First-Class Mail Rate) Commemorative Pane of 20 Stamps: Stamp Fulfillment Services will make an automatic push distribution to Post Offices of a quantity to cover approximately 30 days of sales.
Issue: O Beautiful Stamps
Colors: Black, Cyan, Magenta, Yellow, PMS Cool Gray 7
What:
The Digital Color Postmark measures 2.71″ x 1.16″. 
The Black & White pictorial measures 2.75″ x 1.10″.
FDOI – Frozen Treats Stamps
Typographer: Leslie Badani, Alexandria, VA
The first-day-of-issue dedication ceremony, free and open to the public, will take place at 6 p.m. CDT at Austin’s 
This booklet of 20 stamps showcases the work of Margaret Berg of Santa Monica, CA, depicting whimsical watercolor illustrations of frozen treats. Each of the 10 stamp designs includes two different treats. The words “FOREVER” and “USA” appear along the bottom of each stamp.
Stamp ideas welcome
Background: 
The Digital Color Postmark measures 2.48 x 1.45 inches.
The Black-and-White pictorial measures 2.80 x 1.16 inches.
What: 
The DCP measures 2.34″ x 1.49″ 
The pictorial cancel measures 2.91″ x 1.47″
WHO:
It appears the actual nametag, at least for this flight, read just “Sally.”
On April 6, 2018, in Washington, DC, the U.S. Postal Service ® will issue the STEM Education stamps (Forever ® priced at 50 cents) in four designs, in a pressure-sensitive adhesive (PSA) pane of 20 stamps (Item 477600). The stamps will go on sale nationwide April 6, 2018. The STEM Education pane of 20 stamps may not be split or sold individually.
What: 
Followers of the U.S. Postal Service’s Facebook page can view the ceremony live at facebook.com/USPS.
directed to Hall E on the upper level of the Convention Center for the dedication ceremony.
Fred Rogers (1928-2003) was known as a beloved television neighbor to generations of children. His groundbreaking public television series “Mister Rogers’ Neighborhood” inspired and educated young viewers with warmth, sensitivity and honesty.
There are both Digital Color and pictorial first-day postmarks for this issue. In addition, local post offices may use this postmark:
The Digital Color Postmark measures 2.43″ x 1.43″
The pictorial postmark for this issue measures 2.33″ x 1.49″ 
On March 5, 2018, in Springfield, IL, the U.S. Postal Service will issue the Illinois Statehood First-Class Mail stamp (Forever priced at 50 cents) in one design, in a pressure-sensitive adhesive (PSA) pane of 20 stamps (Item 477100). The stamp will go on sale nationwide March 5, 2018.
The Digital Color Postmark measures 1.86” x 1.45”
The pictorial postmark for this issue measures 2.73” x 1.49” 
The special (local) postmark measures 2.64” x .94”
On each row of stamps, the third and fourth stamps repeat the first two designs. The selvage also features the transparent deep-sea comb jelly (photo by Gregory G. Dimijian) and the firefly squid (photo by Danté Fenolio). Art director Derry Noyes designed the stamps and selvage from existing photographs.
e postmark by mail. They may purchase new stamps at their local Post Office, at The Postal Store website at 
There are 7 
The stamps are unveiled at the Sunrise Theater in Fort Pierce, FL. Left to right, Jeffrey C. Williamson, Chief Human Resources Officer and Executive VP, USPS; Jill Roberts, News Director, WQCS Public Radio; Dr. Edith Widder, CEO and Senior Scientist, Ocean Research & Conservation Association (ORCA); Taylor F. Lockwood, stamp photographer. 
Williamson and other dignitaries sign autographs after the ceremony. 
A set of 10 first day covers canceled at the event. 
The Digital Color Postmark measures 2.97” x 1.38”
The pictorial postmark for this issue measures 2.91” x 1.47”
On February 9, 2018, in Ft. Lauderdale, FL, the U.S. Postal Service® will issue the U.S. Flag 2018 First-Class Mail® stamp (Forever® priced at 50 cents) in one design, in a pressure-sensitive adhesive (PSA) booklet of 20 stamps (Item 678200) produced by security printers Ashton Potter (USA) Ltd (APU) and Banknote Corporation of America (BCA), and a PSA Coil of 100 stamps (Item 749700) produced by security printers APU and BCA. The stamp will go on sale nationwide February 9, 2018.
It measures 2.95” x .95”.
