Remove query strings from WordPress static assets

functions.php

<?php
function remove_query_strings() {
   if(!is_admin()) {
       add_filter('script_loader_src', 'strip_query_string', 15);
       add_filter('style_loader_src', 'strip_query_string', 15);
   }
}

function strip_query_string($src){
   $output = preg_split("/(&ver|\?ver)/", $src);
   return $output[0];
}
add_action('init', 'remove_query_strings');