Are you using the mobile or web app? The mobile and web app always have the most recent and most up to date version of the Exodus 90 Spiritual Exercise. The book is not necessary to have. Some men like to have the book in addition to the app. They use the book in the chapel during their holy hour and the app both to stay connected to their fraternity and for its features that aid in the Exodus 90 Spiritual Exercise and the Day 91 Exercises. Currently the mobile/web app is the only place men can access the Day 91 spiritual exercises after their completion of Exodus 90.
The book can be purchased in your mobile or web app.
From the home screen, click the settings button (gear icon in the top right corner).
From your settings look for the words that say "Buy the Book."
Click "Buy the Book" and follow the prompts for purchasing. The book can be purchased for $30.