Hi,
Please add this custom php code at functions.php of your child theme.
function sf_enqueue_styles_new(){
wp_deregister_style('fontawesome');
wp_dequeue_style( 'fontawesome' )
wp_register_style('fontawesomeNew', '//maxcdn.bootstrapcdn.com/font-awesome/4.2.0/css/font-awesome.min.css', array(), NULL, 'all');
wp_enqueue_style('fontawesomeNew');
}
add_action('wp_enqueue_scripts', 'sf_enqueue_styles_new', 111);
Thanks