https://www.theverge.com/2018/10/30/18041936/apple-watchos-5-1-emoji-watchfaces-update

Update October 30th, 2:08PM ET: A prior version of this article stated that watchOS 5.1 enabled the electrocardiogram app on Apple Watch Series 4 devices. That was incorrect; Apple has said the functionality is coming this year, but it is not part of today’s update. We regret the error.

Apple released watchOS 5.1 today and with it comes support for new emoji, updated watchfaces, and group FaceTime audio. One new watchface includes a “color” face that’ll give users a choice between different shades that take up the whole face.