If you have purchased an Add-on and you reinstall the app or install the app on a different device, you will need to restore your purchases. In some cases, you will need to restore your In-App purchases after the app was updated to a new version.
Note that purchases are bound to your Apple ID. If you log-in on your new/different device with a different Apple ID, you will not be able to restore purchases. So be sure that you are using the same Apple ID that you've used to purchase the Add-on.
👉 To restore your purchases, tap on the menu icon.
👉 Tap on "Add-ons" below
👉 Tap on "Restore purchases"
You may need to enter your password for your Apple ID.
After updating the app from version 3.1.1 or lower to version 3.2.0 or higher, you will need to restore your purchases. This is necessary because the apps data structure has changed and cannot take over your purchases. You will only need to do this only once, and of course, you are not charged again for this purchase.