WooCommerce - Check if you are running a specified WooCommerce version (or higher)

function.php

<?php
function woocommerce_version_check( $version = '2.1' ) {
  if ( function_exists( 'is_woocommerce_active' ) && is_woocommerce_active() ) {
    global $woocommerce;
    if( version_compare( $woocommerce->version, $version, ">=" ) ) {
      return true;
    }
  }
  return false;
}
?>

usage.php

<?php
if( woocommerce_version_check() ) {
    // Use new, updated functions
} else {
    // Use older, deprecated functions
}
?>

<?php echo WC()->version; ?>