Build runs on iPod 4G, doesn't open on iPhone 6 (multiple devices tested)

Hello everyone

I've been working on an app which has a few plugins imported:
- Chartboost
- Unibill
- Facebook SDK

All plugins are up-to-date, and whole project runs without errors or memory leaks.

I build the project to my android device and iPod 4G without any flaws, but 2 of my partners tried to play it on their iPhone 6 but it doesn't work.

The app successful installs on the iPhone 6, but when the icon is tapped, the app immediately closes. When they go to the previous used app screen, it show the app with the unity logo. When they tap that, it crashes too.

Both of the device UDID are registered as developers, also both accounts are registered as beta flight testers of the app.

Has anyone else got the same problem? I've been worried sick because I have no idea where to start fishing.

Thanks!

 

Also;

previous version worked, I'm now trying without facebook plugin, if that doesn't work, I'm deleting unibill aswell.