The Air Force has published a new digital app to help troops stay up-to-date on service knowledge and get ready for testing ahead of promotion. The Air Force Handbook 1 app was released Sept. 6, according to a service news release. The app includes The Air Force Handbook 1 and a study guide, as well as service manuals “The Little Brown Book,” focusing on the enlisted force structure, and “The Little Blue Book,” focusing on the profession of arms. Practice tests, audio and other study tools are also featured. The app is expected to update with the most recent version of the handbook Oct. 1. Read more at AF.mil.