App build on IOS 10 (with target 9.3) doesn't work on IOS 9.3

Just updated my Mac to Sierra (10) and my iPhone to 10.0.2. I have an ionic app built on Sierra Xcode with target to 9.3.
If it runs on IOS 10, it’s OK. If it runs on IOS 9.3, the app shows a blank screen. Investigating now but just want to share my experience.