diff --git a/system/src/Grav/Common/Config.php b/system/src/Grav/Common/Config.php
index df25af870..c3abf1311 100644
--- a/system/src/Grav/Common/Config.php
+++ b/system/src/Grav/Common/Config.php
@@ -55,7 +55,7 @@ class Config extends Data
     {
         // Build file map.
         $files = $this->build();
-        $key = md5(serialize($files) . GRAV_VERSION);
+        $key = md5(json_encode($files) . GRAV_VERSION);
 
         if ($force || $key != $this->key) {
             // First take non-blocking lock to the file.
diff --git a/system/src/Grav/Common/Page/Pages.php b/system/src/Grav/Common/Page/Pages.php
index 39a201d7a..9005ce911 100644
--- a/system/src/Grav/Common/Page/Pages.php
+++ b/system/src/Grav/Common/Page/Pages.php
@@ -173,7 +173,7 @@ class Pages
     {
         $items = $collection->toArray();
 
-        $lookup = md5(serialize($items));
+        $lookup = md5(json_encode($items));
         if (!isset($this->sort[$lookup][$orderBy])) {
             $this->buildSort($lookup, $items, $orderBy, $orderManual);
         }