Bear in mind this is a prerelease app on TestFlight and that Apple would not allow this behavior on the App Store, or even on apps notarized for alternative stores in the EU:
> 2.5.9 Apps that alter or disable the functions of standard switches, such as the Volume Up/Down and Ring/Silent switches, or other native user interface elements or behaviors will be rejected.
Infamously, there was a third party camera app, Camera+, that turned the Volume Up button into a shutter release. Apple pulled it from the store—and then released the same feature for the built in Camera app.
I really hate this rule. The Snapchat camera used to fire with the volume controls and now it is much harder to take a selfie. To add insult to injury, Apple’s own native camera app does this same thing! You can’t even argue that it’s a confusing experience if you, yourself, do it too.
eReaders on iOS suck because they can't have this obvious feature.
You can do some weird keymapping using accessibility options to get a remote keyboard to make page changes if you want.
> 2.5.9 Apps that alter or disable the functions of standard switches, such as the Volume Up/Down and Ring/Silent switches, or other native user interface elements or behaviors will be rejected.
Infamously, there was a third party camera app, Camera+, that turned the Volume Up button into a shutter release. Apple pulled it from the store—and then released the same feature for the built in Camera app.
https://forums.appleinsider.com/discussion/112111/popular-ip...