Had the same issue after the recent update, battery used to last me all day with 20-50% left at the end of the day, after update my battery was dead around 5pm no additional usage than normal. This was reported to samsung who said they would look into it and get back to me yet I haven't heard from them since.
Shocking that they do this to loyal customers its obviously done on purpose to get us to upgrade our phones but after being a Samsung user my entire life i will never buy another one