My iphone 4s sometimes doing die without cause . I'm using OS 9
My iphone 4s sometimes doing die without cause . I'm using IOS 9.1
iPhone 4S, iOS 9.0.2
Depending on the age and use of the phone, the battery needs to be replaced. Visit an Apple Store or an Apple Authorized Service Provider to get it checked.
Find an Apple Authorized Service Provider
iPhone - Contact Support - Apple Support
You can also contact Apple Support and talk to them. They can check the battery online.
Or visit this page to do that: iPhone - Contact Support - Apple Support
Click on Apple Support, then on ->Battery, Power &Charging ->Battery questions and troubleshooting, and follow the instructions.