App Crashes Only On Testflight Build

Question

I have created an app on swift and tested it extensively using iPhone 6, iPhone 6 plus and iPhone 5 devices and all the simulators offered in Xcode. The app runs fine and do

Answer 1

In my case, changing Legacy Build System to New Build System (for Xcode 10) solves my issue where Testflight build behaves differently. Might be helpful to someone.