This method is perfect if you've never downloaded GarageBand before but have access to another device running a newer iOS version.
Here’s how to successfully get a compatible version of GarageBand onto your iOS 15.7 device. These methods rely on Apple's built-in system for providing "last compatible versions" of apps. garageband ios 157 download link
: The ability to build complex arrangements with up to 32 tracks. External Integration : Support for Audio Unit Extensions This method is perfect if you've never downloaded