iOS crash after splash screen

Hello, I am currently trying to get an app on iPhones. We have succeeded with iPhones 6+ versions and up. But, anything below an iPhone 6 will cause the app to crash after the splash screen. We have spent an entire week with trial and error trying to get it to work. We have been searching the forums day and night, messing with the device profiles and correcting the small bugs that come with 4.13 and 4.14, and decreasing texture quality and it all seems to no avail. So, if anyone has any kind of suggestions, please help out. Thanks.

Could you attach logs from your device when crash occured?