We have an iPhone 6s that was replaced by Apple right before it was replaced with a newer model phone. The battery health indicator says it is at 95 percent. My son is using the phone for summer day camp as he doesn’t want to take his nicer phone. He says the battery life is terrible. I’m wondering if he is just used to higher capacity batteries...like 7 plus and X batteries. I’m happy to replace the battery but Apple said it won’t make a difference.