I found 2 other books that are slated to release on December 26, 2017!
First, GOTY 2018's second book is up for that date! It is also written by Erin Teagan.
Lastly, there's a new Real Stories from My Time on that date as well! It is about the Underground Railroad and features Addy.
"The Real Stories From My Time chapter book series pairs nonfiction content with beloved American Girl BeForever characters, offering readers a unique entry point into important events in American history. Perfect for book reports with full-page illustrations throughout, plus historical photos, maps, a timeline, a glossary, and bibliography at the back. The Underground Railroad includes miles of real stories of passengers, conductors, and abolitionists, well-known and unknown, that made their mark on history. Throughout, BeForever character Addy Walker shares snippets of her own gripping fictional story of escaping slavery.