hey guys so my very first iphone was the 64gb 4s and i loved it (and still do). on Oct 7, 2014, i had to swap with my mom cuz she didnt like her 16gb iphone 6 plus. well, now i have my iphone 4s back but found out that she updated the 4s to iOS 9.2. seriously like every few minutes when i look at the phone, it has lost another 3% battery life or so...it drains RAPIDLY!!! yesterday, i noticed it dropped from 100% to 95% in like 5 minutes and i wasnt even using the phone... it used to have such a great battery life and i dont know if this sudden drop is from the new iOS 9.2 (i probably used to be on iOS 7 or 8 back when i traded her...i didnt update very often) or if it is just because its a really old phone. its a bit less responsive also (might swipe or press home button and reaction only happens like 3-4 seconds later every once in a while, not constantly - that would be too annoying). basically, its still a good phone, i just want to make it as good as it can possibly be. i have an iphone SE that i use mainly and this 4s is basically just for other apps and media i dont want on my main phone (basically use it like an ipod now). should i go ahead and install 9.3.1? will/is this be jailbreak-able (im only interested in doing this to go back down to a more primitive iOS)? any other tips on how to make this battery life better? (this isnt my primary phone so i can play around with it a little bit) thanks a lot guys!