Missing emoticons or smilies

We rarely use emoticons on our websites but today we wanted to insert a <3 heart emoticon in a post. We used the <3 in a sentence, away from other punctuation and code, but the emoticon didn’t show up. The basic emoticons, like 😉 do show up when inserted in the same place.

Googling revealed that the heart is part of a new WP emoticon set from 2014. I checked my WP smilies directory and I only see the original set. None of the image titles had the word heart in it. I’m using WP 4.31 and testing via Mac browsers Safari and Firefox.

I checked another 4.31 site we have and saw the same thing – no expanded smilies directory.

Where can I find and add the extra smilies?