Declare properties static

ai-simplesitestats.php

@@ -109,7 +109,7 @@ class StatisticsPage {
 
 class AiSSS {
 
-    private $version = '0.0.1', $blog_id;
+    private static $version = '0.0.4', $blog_id;
 
     public function __construct() {
         global $blog_id;