I am facing the same problem of battery drainage with my Galaxy S8 as I was facing before with Galaxy A5 2016. After few updates the battery started draining fast in Galaxy S8 and the same happened with my Galaxy A5 2016 After few software and security patch update. It going down from 10% to 0% like in 15 secs and then switched off. Is it some kind of marketing strategies of yours so buyers buy your new phones cause their old samsung phones are draining fast. If that so this is very cheap strategy of yours. No one wants to waste money on some kind of pathetic hatdware or else Please make your batteries more durable or release a stable update for this problem. Otherwise you might loose one of your loyal customer from India soon.
There are plenty of other brands with good battery life.
