Are Lightning headphones only working with iPhone 7 or also with older devices? With iPhone 7 Apple introduced headphones connected with Lightning Connector.

Are these headphones also compatible with older iPhones? Are there any limitations by using it with older devices? Which iOS version is needed for this feature?

For example I am currently using an iPhone 6 Plus with iOS 10.2. Will it work?
According to the Apple product page, any device with a Lightning port and iOS 10 is compatible.