When you purchase an app or make an in-app purchase it is linked to your Google or Apple(iOS) account. The purchase should transfer across to any device which is logged into the same account. It can sometimes take a few hours for this to work.
If you are having problems accessing the pro purchase, make sure that your devices are connected to the internet and try re-starting them.
Android and Apple(iOS) are separate platforms. Even though the same apps will often appear on both, they are different things and purchases will not automatically transfer across between them.
To avoid having lots of apps making sound at the same time, Android has something called audio focus. When you play a music app it will hold this audio focus. However, if you open another one it will 'steal' the focus and start playing instead.
Our Metronome Beats app has a Preferences option to 'Ignore audio focus' which will allow it to keep playing with other music apps. On some phones you will also need to add Metronome Beats to the 'Protected Apps' list on the phone to get this to work properly.
As long as your device is still logged into the same account that you purchased the app from you shouldn't have to pay again. Search for the app on the Play or Apple app store and you should see the option to install it.
If you are getting errors that your compass won't work or is not available the most likely cause is that your phone doesn't have a magnetometer sensor. Most compass apps work by using readings from this sensor, however not all phones have one (particularly cheaper ones).
You can find more information on this here.
You can manage your subscription from your phone by doing the following: