Battery drops from 100% to dead in a couple of hours.

I have a iPhone 6s that has issues with its battery losing capacity quickly. The battery was changed by Apple about a year ago on warranty. The battery health according to the app says 97%. Nothing else showing any issues in the app. The phone has gone from 100% to 0% and dead in seconds after the latest OS update.. I turned it back on and it was ok. I've turned off all the application that drain power while its "off". Today, it went from 100% to 5% within a couple of hours. I'm at a loss as to what to do. Googling this issue, I see there seems to be a lot of people with this same problem. Is there a solution?