From simple smiley faces and love hearts to high heels ... iPhone users will have access to eight new emoji. And there is one face that everyone is already saying will be their favourite.

However, the Happy Face Killer nickname came from taunting notes Jesperson left authorities, which featured a pre-emoji written smiling face, as depicted in the series. "He'd even leave messages ...

At Applaudo Studios, a web design firm in El Salvador, Slack conversations are peppered with emoji of employees making silly faces ... most popular include a happy face with tears of joy ...

The series is inspired by the true story of Keith Hunter Jesperson, infamously known as the Happy Face Killer ... He earned his nickname for the smiley faces he included in letters sent to ...