If you recently downloaded the upgrades, you might want to try changing some of the settings on your phone like I did after reading about the impact the new upgrades had on iPhones. Saved me from buying a new phone! With the changes I made to my iPhone settings, I no longer have the battery drain problem.
My Verizon iPhone 4S began losing its charge after I downloaded the recent upgrades. Prior to the upgrade, I had no issue with battery drain, and after the upgrade I was down to 0% by noon! After visiting Verizon where they advised only Apple was authorized to open the phones, I did my own online research and found that the recent upgrades caused battery drain for many iphone users with older model phones (yes, my 1.5 year old phone is an "OLDER MODEL", just like me! LOL). I changed the settings on my phone (I already had the auto brightness off), and ONE in particular I think was the clincher for me: turning off spotlight search. I don't use that search, I use Google or Safari for internet search, and search within Contacts or email for those searches.
Here is the article I used to change my settings, I thought it was nice and clear:
6 tips and tricks for iOS 7 | ExtremeTech
There are later articles with similar suggestions, perhaps even more suggested setting changes by now, hope this helps and isnt' too late.