WordPress/wp-admin/ms-upgrade-network.php

<?php
require_once('admin.php');

if ( !is_multisite() )
	wp_die( __('Multisite support is not enabled.') );

require_once( ABSPATH . WPINC . '/http.php' );

$title = __('Update Network');
$parent_file = 'ms-admin.php';
require_once('admin-header.php');

if ( ! current_user_can( 'manage_network' ) )
	wp_die( __('You do not have permission to access this page.') );

echo '<div class="wrap">';
screen_icon();
echo '<h2>'.__('Update Network').'</h2>';

$action = isset($_GET['action']) ? $_GET['action'] : 'show';

switch ( $action ) {
	case "upgrade":
		$n = ( isset($_GET['n']) ) ? intval($_GET['n']) : 0;

		if ( $n < 5 ) {
			global $wp_db_version;
			update_site_option( 'wpmu_upgrade_site', $wp_db_version );
		}

		$blogs = $wpdb->get_results( "SELECT * FROM {$wpdb->blogs} WHERE site_id = '{$wpdb->siteid}' AND spam = '0' AND deleted = '0' AND archived = '0' ORDER BY registered DESC LIMIT {$n}, 5", ARRAY_A );
		if ( empty( $blogs ) ) {
			echo '<p>' . __( 'All done!' ) . '</p>';
			break;
		}
		echo "<ul>";
		foreach ( (array) $blogs as $details ) {
			if ( $details['spam'] == 0 && $details['deleted'] == 0 && $details['archived'] == 0 ) {
				$siteurl = get_blog_option( $details['blog_id'], 'siteurl' );
				echo "<li>$siteurl</li>";
				$response = wp_remote_get( trailingslashit( $siteurl ) . "wp-admin/upgrade.php?step=1", array( 'timeout' => 120, 'httpversion' => '1.1' ) );
				if ( is_wp_error( $response ) )
					wp_die( "<strong>Warning!</strong> Problem updating {$siteurl}. Your server may not be able to connect to sites running on it.<br /> Error message: <em>" . $response->get_error_message() ."</em>" );
				do_action( 'after_mu_upgrade', $response );
				do_action( 'wpmu_upgrade_site', $details[ 'blog_id' ] );
			}
		}
		echo "</ul>";
		?><p><?php _e("If your browser doesn't start loading the next page automatically click this link:"); ?> <a class="button" href="ms-upgrade-network.php?action=upgrade&amp;n=<?php echo ($n + 5) ?>"><?php _e("Next Sites"); ?></a></p>
		<script type='text/javascript'>
		<!--
		function nextpage() {
			location.href = "ms-upgrade-network.php?action=upgrade&n=<?php echo ($n + 5) ?>";
		}
		setTimeout( "nextpage()", 250 );
		//-->
		</script><?php
	break;
	case 'show':
	default:
		?><p><?php _e("You can update all the sites on your network through this page. It works by calling the update script of each site automatically. Hit the link below to update."); ?></p>
		<p><a class="button" href="ms-upgrade-network.php?action=upgrade"><?php _e("Update Network"); ?></a></p><?php
		do_action( 'wpmu_upgrade_page' );
	break;
}
?>
</div>

<?php include('admin-footer.php'); ?>