Get in touch, and find quick answers to the questions that come up most.
For a suggestion, a mistake you spotted, a missing topic or a problem, email sincere.apps@gmail.com. You can also do this from inside the app: open Settings and tap Suggestion, Report a problem or Ask a question. That opens Mail with the app version and your device filled in, or a short form if the device has no Mail. The Tools and Training shelves have their own buttons for recommending a tool or a kind of practice.
The app plays with the silent switch on, so the switch is not the cause. Check the volume with the side buttons: the app shows a short notice the first time you play something at zero volume. If a Bluetooth speaker or headphones are paired, check them too. If there is still no sound, close the app from the app switcher and open it again.
The book has three shelves: Beginner, Intermediate and Advanced. Each chapter has a few pages to read, where every idea is played and most pages have something to try; then Try, guided practice with worked examples; then a Play game; then a Check of ten questions. Eighty percent on the Check marks the chapter as mastered. Nothing is locked: you can read any chapter in any order, though each one lists what it builds on.
On the shelf, Find my level walks through the chapters three questions at a time and stops at the first one you miss. It is a suggestion of where to start, not a lock.
Melody Dictation, Sight Reading and Rhythm Reading each have 120 lessons that add one thing at a time; the Interval Trainer pairs every interval with a song; Drills ask about notes, intervals, chords, scales and progressions on the staff, on the keyboard and by ear. All of it is separate from the lessons, so you can dip in whenever you have five minutes.
On your device only. Pages read, scores, mastery and the loops you compose stay in the app's own storage and are not sent anywhere. Deleting the app deletes them. Settings has a Reset all progress button if you want to start again; it keeps your saved loops.
Yes, completely. Nothing in the lessons or the training needs a connection. Only sending feedback does.
Any purchase goes through Apple, so refunds do too: visit reportaproblem.apple.com, sign in and pick the purchase. If you reinstall or change phones, use Restore Purchases where it is offered; an unlock is tied to your Apple ID.
Music is drawn with the Bravura font under the SIL Open Font License; the full licence text is in the app under Settings, Licences.