diff --git a/Addon.ini b/Addon.ini
index f186660..e9a51af 100644
--- a/Addon.ini
+++ b/Addon.ini
@@ -1,4 +1,4 @@
 
 Addon_Name		= 'Typesetter Core'
 Addon_Unique_ID		= 40
-Addon_Version		= 5.3-p8.3 
\ No newline at end of file
+Addon_Version		= 5.3.1 
\ No newline at end of file
diff --git a/include/common.php b/include/common.php
index 4f90810..692c74a 100644
--- a/include/common.php
+++ b/include/common.php
@@ -50,7 +50,7 @@ gp_defined('CMS_NAME_FULL',				'Typesetter CMS');
 gp_defined('addon_browse_path',			CMS_DOMAIN . '/index.php');
 gp_defined('debug_path',				CMS_DOMAIN . '/index.php/Debug');
 
-gp_defined('gpversion',					'5.3-p8.3');
+gp_defined('gpversion',					'5.3.1');
 gp_defined('gp_random',					\gp\tool::RandomString());
 
 
diff --git a/include/thirdparty/css-crush/lib/CssCrush/Crush.php b/include/thirdparty/css-crush/lib/CssCrush/Crush.php
index 82f1fb1..230d607 100644
--- a/include/thirdparty/css-crush/lib/CssCrush/Crush.php
+++ b/include/thirdparty/css-crush/lib/CssCrush/Crush.php
@@ -97,7 +97,7 @@ class Crush
         }
     }
 
-    public static function plugin($name = null, callable $callback = null)
+    public static function plugin($name = null, callable|null $callback = null)
     {
         static $plugins = [];
 
diff --git a/include/thirdparty/css-crush/lib/CssCrush/Functions.php b/include/thirdparty/css-crush/lib/CssCrush/Functions.php
index 5532aa5..c8b6021 100644
--- a/include/thirdparty/css-crush/lib/CssCrush/Functions.php
+++ b/include/thirdparty/css-crush/lib/CssCrush/Functions.php
@@ -53,7 +53,7 @@ class Functions
         $this->pattern = Functions::makePattern(array_keys($this->register));
     }
 
-    public function apply($str, \stdClass $context = null)
+    public function apply($str, ?\stdClass $context = null)
     {
         if (strpos($str, '(') === false) {
             return $str;
diff --git a/include/thirdparty/css-crush/lib/CssCrush/Options.php b/include/thirdparty/css-crush/lib/CssCrush/Options.php
index 0081e10..54b87ce 100644
--- a/include/thirdparty/css-crush/lib/CssCrush/Options.php
+++ b/include/thirdparty/css-crush/lib/CssCrush/Options.php
@@ -33,7 +33,7 @@ class Options
         'newlines' => 'use-platform',
     ];
 
-    public function __construct(array $options = [], Options $defaults = null)
+    public function __construct(array $options = [], ?Options $defaults = null)
     {
         $options = array_change_key_case($options, CASE_LOWER);
 
@@ -169,7 +169,7 @@ class Options
         return $computed ? $this->computedOptions : self::filter($this->inputOptions);
     }
 
-    public static function filter(array $optionsArray = null)
+    public static function filter(?array $optionsArray = null)
     {
         return $optionsArray ? array_intersect_key($optionsArray, self::$standardOptions) : self::$standardOptions;
     }
diff --git a/include/thirdparty/css-crush/lib/CssCrush/StringObject.php b/include/thirdparty/css-crush/lib/CssCrush/StringObject.php
index 18b4eec..db8ec7a 100644
--- a/include/thirdparty/css-crush/lib/CssCrush/StringObject.php
+++ b/include/thirdparty/css-crush/lib/CssCrush/StringObject.php
@@ -8,6 +8,8 @@ namespace CssCrush;
 
 class StringObject
 {
+	public string|null $raw = null;
+	
     public function __construct($str)
     {
         $this->raw = $str;
diff --git a/include/thirdparty/css-crush/lib/CssCrush/Tokens.php b/include/thirdparty/css-crush/lib/CssCrush/Tokens.php
index 7726955..f40510f 100644
--- a/include/thirdparty/css-crush/lib/CssCrush/Tokens.php
+++ b/include/thirdparty/css-crush/lib/CssCrush/Tokens.php
@@ -11,7 +11,7 @@ class Tokens
     public $store;
     protected $ids;
 
-    public function __construct(array $types = null)
+    public function __construct(?array $types = null)
     {
         $types = $types ?: [
             's', // strings.
diff --git a/include/thirdparty/css-crush/lib/CssCrush/Util.php b/include/thirdparty/css-crush/lib/CssCrush/Util.php
index f0743e2..843ffb9 100644
--- a/include/thirdparty/css-crush/lib/CssCrush/Util.php
+++ b/include/thirdparty/css-crush/lib/CssCrush/Util.php
@@ -8,7 +8,7 @@ namespace CssCrush;
 
 class Util
 {
-    public static function htmlAttributes(array $attributes, array $sort_order = null)
+    public static function htmlAttributes(array $attributes, ?array $sort_order = null)
     {
         // Optionally sort attributes (for better readability).
         if ($sort_order) {
@@ -75,7 +75,7 @@ class Util
         return $path;
     }
 
-    public static function resolveUserPath($path, callable $recovery = null, $docRoot = null)
+    public static function resolveUserPath($path, ?callable $recovery = null, $docRoot = null)
     {
         // System path.
         if ($realpath = realpath($path)) {