diff --git a/includes/components/response/templateresponse.class.php b/includes/components/response/templateresponse.class.php
index 4b165c82..6353e87d 100644
--- a/includes/components/response/templateresponse.class.php
+++ b/includes/components/response/templateresponse.class.php
@@ -37,14 +37,20 @@ trait TrListPage
     public function getCacheKeyComponents() : array
     {
         // max. 3 catgs
-        // catg max 65535
+        // catg max 32767 - largest in use should be 11.197.26801 (Spells: Professions > Tailoring > Spellfire Tailoring)
         if ($this->category)
         {
             $catg = 0x0;
             for ($i = 0; $i < 3; $i++)
             {
-                $catg <<= 4;
-                $catg |= ($this->category[$i] ?? 0) & 0xFFFF;
+                $catg <<= 4 * 4;
+                if (!isset($this->category[$i]))
+                    continue;
+
+                if ($this->category[$i])
+                    $catg |= ($this->category[$i] << 1) & 0xFFFF;
+                else
+                    $catg |= 1;
             }
         }
 
diff --git a/includes/kernel.php b/includes/kernel.php
index 00a4414d..b2f43938 100644
--- a/includes/kernel.php
+++ b/includes/kernel.php
@@ -6,7 +6,7 @@ mb_internal_encoding('UTF-8');
 error_reporting(E_ALL);
 mysqli_report(MYSQLI_REPORT_ERROR);
 
-define('AOWOW_REVISION', 42);
+define('AOWOW_REVISION', 43);
 define('OS_WIN', substr(PHP_OS, 0, 3) == 'WIN');            // OS_WIN as per compile info of php
 define('CLI', PHP_SAPI === 'cli');
 define('CLI_HAS_E', CLI &&                                  // WIN10 and later usually support ANSI escape sequences