IPhone 4s battery drain since ios 6.1?

I have iPhone 4s and it seems that since ios 6.1 my battery life has reduced a lot. I used to be putting my phone on charge at night easily with 30% battery and now it is much less and I think it has had less usage as the job I'm currently on gives me a lot less chance to quickly unlock and refresh emails etc. Anyone else with this problem?

Some iPhone users are seeing battery drain and overheating issues after upgrading to iOS 6.1

http://thenextweb.com/apple/2013/02/08/some-iphone-users-are-seeing-battery-drain-and-overheating-issues-after-upgrading-to-ios-6-1/