The InnoCaption app was previously able to change and save your default sound output setting to speaker mode (from regular phone mode) for easier use while viewing captions. However, this is no longer possible starting from iOS 12.4 and after due to a change in Apple's policies.
However, you can still manually change your default sound output settings for all calls to speaker mode, which will make your captioned calls through InnoCaption easier. Please note that this will also change the default option for calls made or received through your regular phone dialer as well.
To change your iPhone default sound output setting
From your home screen, open the Settings app
Tap Accessibility
Tap Touch
Scroll down and tap Call Audio Routing
Select Speaker
If you ever need to change your sound output setting (for example, to a bluetooth device) for an individual call on the InnoCaption app, you can do so easily by following the steps below.
To switch between sound output modes during a call
During a live call, tap the Audio icon on the bottom toolbar, to the left of the end call icon
Select your preferred sound output mode
Tap the caption screen and the selected sound output mode will be displayed