ENQUEUE SCRIPTS AND STYLES WITH AUTOMATIC VERSIONING

functions.php

//Instead of WP default
//<link rel='stylesheet' id='child-theme-css'  href='http://mysite.com/wp-content/themes/child/css/styles.min.css?ver=4.3.1' type='text/css' media='all' />
//You get this every time the minified CSS is saved and compressed:
//<link rel='stylesheet' id='child-theme-css'  href='http://mysite.com/wp-content/themes/child/css/styles.min.css?ver=1447781986' type='text/css' media='all' />

<?php
$themecsspath = get_stylesheet_directory() . '/css/styles.min.css';

wp_enqueue_style(
	'child-theme',
	get_stylesheet_directory_uri() . '/css/styles.min.css',
	array(),
	filemtime( $themecsspath )
);