Hi there,
The previous option that was available in the Theme Option was remove because the site icons option is now native to Wordpress but it only uses one site icon.
You could add your specific site icon by adding some additional codes to functions.php file of the child theme.
The code should be:
add_action('wp_head', 'add_code_header');
function add_code_header(){
?>
<link rel="apple-touch-icon-precomposed" sizes="57x57" href="LINK_TO_THE_ICON_IMAGE" />
<link rel="apple-touch-icon-precomposed" sizes="114x114" href="LINK_TO_THE_ICON_IMAGE" />
<link rel="apple-touch-icon-precomposed" sizes="72x72" href="LINK_TO_THE_ICON_IMAGE" />
<link rel="apple-touch-icon-precomposed" sizes="144x144" href="LINK_TO_THE_ICON_IMAGE" />
<link rel="apple-touch-icon-precomposed" sizes="60x60" href="LINK_TO_THE_ICON_IMAGE" />
<link rel="apple-touch-icon-precomposed" sizes="120x120" href="LINK_TO_THE_ICON_IMAGE" />
<link rel="apple-touch-icon-precomposed" sizes="76x76" href="LINK_TO_THE_ICON_IMAGE" />
<link rel="apple-touch-icon-precomposed" sizes="152x152" href="LINK_TO_THE_ICON_IMAGE" />
<link rel="icon" type="image/png" href="LINK_TO_THE_ICON_IMAGE" sizes="196x196" />
<link rel="icon" type="image/png" href="LINK_TO_THE_ICON_IMAGE" sizes="96x96" />
<link rel="icon" type="image/png" href="LINK_TO_THE_ICON_IMAGE" sizes="32x32" />
<link rel="icon" type="image/png" href="LINK_TO_THE_ICON_IMAGE" sizes="16x16" />
<link rel="icon" type="image/png" href="LINK_TO_THE_ICON_IMAGE" sizes="128x128" />
<?php
}
Please change LINK_TO_THE_ICON_IMAGE to the full URL of the image files.
You may also remove the lines of code that you do not need the specific sizes of the image icon to be added on your site.
Hope this helps.