battery issues on 10.2.1?

Try the suggestions here: If your iPhone, iPad, or iPod touch won't charge - Apple Support

backup ur device then reinstall an new copy of iOS 10.2.1 see if you still have the same issue. if you dont then use that version of iOS. if you still do then contact apple, or deal with it until the next update is released. since this issue is only present once you've updated to iOS 10.2.1, it should only be an software issue , not hardware.
<Edited by Host>

Hi elleyes17,

I just want to know if you did find a solution to this issue?

The exactly same thing happened to me and now my phone takes around 6 hrs to charge and I lose 1% of battery every 2min.

It all started right after the update, before the update I usually charged my iPhone every 2 days because I don't really use it.

I'm really frustrated

http://www.apple.com/ca/batteries/maximizing-performance/

funny you say that, ive seen many others saying the same. mine too.😕