I've heard that 8.1 has a battery issue problem. As I bought my phone, I updated it to 8.1 and haven't experience the performance of 8.0.

I'm more concern on its battery life. It only lasts 7-8 hours on watching movies. And when I'm surfing the net over wifi, it only lasts 14 hours straight.

I want to downgrade my software to 8.0 to experience good battery life as they recommend to turn back to 8.0 as it offers good battery performance. I'm just worried that it might affect the warranty.