The Series 4 is the first truly big update to the Apple Watch line. It changes everything: the display, size, the shape, the sensors, the processor, the speaker and microphones—you name it. It truly elevated Apple’s wrist-wearable to a new level, but its most exciting new feature has been missing action since the Series 4's September launch.
With today's release of watchOS 5.1.2, though, that feature is finally here. Apple has given us the first smartwatch with a built-in electrocardiogram (ECG) feature (and they say Apple doesn’t innovate anymore!).