Older version of the gospel library app

I have an iPhone 8plus that was given to us. It is running ios 16.7.15 and it can not upgrade to ios 17. I want to put the gospel library app on this device for my kids. I need an older version that works with this version of ios. The account the device is logged into has not downloaded the gospel library app for ios before so we can't get older versions from the app store. Where can I download an older version that is compatible with this apple device?

I don't know for sure if this would work, but if you have a newer iOS device, you could try temporarily signing into that newer device with the same Apple Account as the iPhone 8 Plus, and download Gospel Library. That will associate Gospel Library to your child's Apple Account. Then, go back to the iPhone 8 Plus and look in your previously-installed or "purchased" apps to see if Gospel Library is listed.