Upgrading ios version

Hi,
I want to update IOS version of my device. What will happen to my game's progress if I upgrade the ios version? Should I start from the beginning?

Moved to video game area

I didn't have a game in progress when I updated my iPad.   I will say that my purchases and unlocked variants were still there after I upgraded.   

Upgrading your iOS version will do nothing to the Sentinels app.

However, using iOS will mean you get the game later than everyone else.