Its still mechanical as before as I heard.
"Fingerprint scanner
The optional fingerprint scanner rescues Apple's reputation as a smartphone maker with cutting-edge features that actually influence how people use their phones. The new scanner, called the Touch ID sensor, is integrated into the home button and adds some classy materials with its sapphire crystal topper and "stainless-steel detection ring." Now you tap to activate your phone, instead of pressing the button (but the button still depresses for normal navigation actions".