iPhone 6s shuts down with 30 to 40 % of battery life

Good evening,

since when I've updated my iPhone 6s to iOS 10 I've noticed that the phone always shuts down with 30 to 40 % of battery life remaining. Then if I try to power on the phone it says that it has no charge, but If I plug the phone to the line with the power chord it can power on immediately and it notify's the right power remaining (30 to 40). After this it works right till the complete battery discharge.

Has anyone the same problem? Or can anyone suggest me how to solve this issue?

Thank you in advice.