diff --git wp-admin/includes/class-wp-upgrader.php wp-admin/includes/class-wp-upgrader.php
index ef8fb5f..f77c645 100644
--- wp-admin/includes/class-wp-upgrader.php
+++ wp-admin/includes/class-wp-upgrader.php
@@ -107,6 +107,10 @@ class WP_Upgrader {
 
 	function download_package($package) {
 
+		$reply = apply_filters('upgrader_pre_download', false, $package, $this);
+		if ( false !== $reply )
+			return $reply;
+
 		if ( ! preg_match('!^(http|https|ftp)://!i', $package) && file_exists($package) ) //Local file or remote?
 			return $package; //must be a local file..