My note 5 battery is draining so fast after the latest nougat update

[Android Central Question]

I upgraded the OS of my note to nougat about a year ago but lately when I just had a minor update about a month ago my battery happened to drain so abnormally and fast. I wiped out the cache for 3 times and also did a reset factory 3 times but none solved the problem the battery keeps draining fast.
As far as I remember it lasted for about one full day with a quite heavy use but now with same rate of usage or even less the battery lasts no longer than 12 hours.
shall I wait for another update to be released or just replace the battery?!

 

[B. Diddy]

Welcome to Android Central! Did the battery life suddenly drop, or has it been more gradual?

 

[amir tabrizi]

Welcome to Android Central! Did the battery life suddenly drop, or has it been more gradual?

thank you!
no, it was not gradual. as I installed the latest update the battery began to behave abnormally and didn't last as much as before nearly half the prior life.

 

[B. Diddy]

If it was a sudden change, it seems unlikely to be a battery problem. It might be a good idea to try reinstalling the firmware using Smart Switch, in case there was a problem with the update process. http://www.sammobile.com/forum/showthread.php?t=29914

 

[amir tabrizi]

If it was a sudden change, it seems unlikely to be a battery problem. It might be a good idea to try reinstalling the firmware using Smart Switch, in case there was a problem with the update process. http://www.sammobile.com/forum/showthread.php?t=29914

yeah, I have to do so.
but let me say sth that seems very fishy
https://www.sammobile.com/news/samsung-denies-slowing-down-phones-with-older-batteries-once-again/
as you can see in this post despite being denied by the Samsung officials I think maybe sth is done by the company while releasing new updates because I've asked some of my friends who own note 5, they are also experiencing the same battery problem.
but as u said if the problem continues to exist I should try to reinstall the firmware using the software you suggested.
thank you, Mr. B. Diddy, you were of great help here and I appreciate it.

 

[amir tabrizi]

I tried the suggested way, using the smart switch but recently they have omitted the emergency initialization option so I couldn't do it with the PC. I found another way which was Odin software i installed it on my laptop and downloaded the latest stock firmware and installed it successfully and the problem seems to be solved for now.
I shall wait and see whether the problem exists anymore or not.