iPhone IOS Question

My iPhone 6 has been updated with the 9.2.1 soon after it came out. More recently I have been having wacky battery issues.

The last couple times I have plugged my phone into the computer it gives me the pop up that says there is an update to my IOS and the update is 9.2.1.

Does my phone software have a corruption?
If I run the update, will it work?
Wondering if it will help with my battery issue...

Thanks for any insight or experience.