WordPress Plugin - clear permalinks on Network Upgrade. If you have sites on a WP Network (formerly WPMU) that use custom permalink structures or certain configurations of Custom Post Types it may be necessary to flush permalinks. This hack lets you do that safely across the entire network. Add this file to /wp-content/mu-plugins/ or as a enable…

upgrade-permalinks.php

<?php
/*
Plugin Name: MU Clear Permalinks
Plugin URI: https://gist.github.com/dalethedeveloper/5492196
Description: Clear all site permalinks when Update Network is used
Author: dalethedeveloper
Version: 0.1
*/

if( ! function_exists('rhplive_clear_permalinks') ):
function rhplive_clear_permalinks($id) {
	switch_to_blog($id);
	flush_rewrite_rules();
	restore_current_blog();
}
endif;
add_action('wpmu_upgrade_site','rhplive_clear_permalinks');