"Any older iPhone models are currently not affected, including the iPhone 5s, iPhone 5c, iPhone 5, iPhone 4s, iPhone 4, iPhone 3Gs, iPhone 3G, and the original iPhone, even though some of those models have also experienced shutdowns. The latest iPhone 8, iPhone 8 Plus, and iPhone X are also currently not affected."
Not affected is a misnomer. The "fix" has not been IMPLEMENTED. Apple has already announced that the "fix" will be implemented for the 8 and up in the future. The use of "fix" is of course, a misnomer itself. It is NOT a fix but a workaround for poorly performing batteries.