Iphone 6s plus Battery draining too fast after upgrade

Hey Guys,

As I have mentioned in the subject line my phones issue is that battery is draining too fast from 100 to 0% within just 5 to 6 hrs.

After ios 13.3 upgrade I am facing this issue.Before it was performing well.

If I play songs/media/movie for a while --->It hardly last for 4 to 4.5 hrs before it used to last for more than 8 hrs.

On standby ---->8 hr max before it used to last for a whole day leaving behind 10-20% for the next day in single charge.

Now I have to charge at least twice to last my phone for a day.Can you guys please tell me why this is happening is there something that related to latest updates?