diff --git a/README.md b/README.md
index acfb312..00e51f1 100644
--- a/README.md
+++ b/README.md
@@ -15,7 +15,7 @@ This repository contains the PrestaShop wallee payment module that enables the s
 
 ## Documentation
 
-* [English](https://plugin-documentation.wallee.com/wallee-payment/prestashop-1.6/1.2.34/docs/en/documentation.html)
+* [English](https://plugin-documentation.wallee.com/wallee-payment/prestashop-1.6/1.2.36/docs/en/documentation.html)
 
 ## Support
 
@@ -23,7 +23,7 @@ Support queries can be issued on the [wallee support site](https://app-wallee.co
 
 ## License
 
-Please see the [license file](https://github.com/wallee-payment/prestashop-1.6/blob/1.2.34/LICENSE) for more information.
+Please see the [license file](https://github.com/wallee-payment/prestashop-1.6/blob/1.2.36/LICENSE) for more information.
 
 ## Other PrestaShop Versions
 
diff --git a/docs/en/documentation.html b/docs/en/documentation.html
index b1d2695..9f218c9 100644
--- a/docs/en/documentation.html
+++ b/docs/en/documentation.html
@@ -22,7 +22,7 @@ <h2>Documentation</h2>				</div>
 		</a>
 	</li>
 	<li>
-		<a href="https://github.com/wallee-payment/prestashop-1.6/releases/tag/1.2.34/">
+		<a href="https://github.com/wallee-payment/prestashop-1.6/releases/tag/1.2.36/">
 			Source
 		</a>
 	</li>
@@ -54,7 +54,7 @@ <h1>
 					<div class="olist arabic">
 <ol class="arabic">
 <li>
-<p><a href="https://github.com/wallee-payment/prestashop-1.6/releases/tag/1.2.34/">Download</a> the module.</p>
+<p><a href="https://github.com/wallee-payment/prestashop-1.6/releases/tag/1.2.36/">Download</a> the module.</p>
 </li>
 <li>
 <p>Login to the backend of your PrestsShop store.</p>
diff --git a/inc/Exception/Incompleteconfig.php b/inc/Exception/Incompleteconfig.php
index ac8058d..a4df093 100644
--- a/inc/Exception/Incompleteconfig.php
+++ b/inc/Exception/Incompleteconfig.php
@@ -24,7 +24,7 @@ class WalleeExceptionIncompleteconfig extends Exception
      * @param Throwable|null $previous
      *   The previously thrown exception.
      */
-    public function __construct($message = "The configuration is not complete", int $code = 0, ?Throwable $previous = null) {
+    public function __construct($message = "The configuration is not complete", $code = 0, Throwable $previous = null) {
         parent::__construct($message, $code, $previous);
     }
 }
diff --git a/inc/Helper.php b/inc/Helper.php
index 4cc9d7f..9d76a36 100644
--- a/inc/Helper.php
+++ b/inc/Helper.php
@@ -11,9 +11,9 @@
 
 class WalleeHelper
 {
-	public const SHOP_SYSTEM = 'x-meta-shop-system';
-	public const SHOP_SYSTEM_VERSION = 'x-meta-shop-system-version';
-	public const SHOP_SYSTEM_AND_VERSION = 'x-meta-shop-system-and-version';
+	protected static $shop_system = 'x-meta-shop-system';
+	protected static $shop_system_version = 'x-meta-shop-system-version';
+	protected static $shop_system_and_version = 'x-meta-shop-system-and-version';
 
     private static $apiClient;
 
@@ -675,11 +675,18 @@ public static function getMaxExecutionTime()
 	protected static function getDefaultHeaderData()
 	{
 		$shop_version = _PS_VERSION_;
-		[$major_version, $minor_version, $_] = explode('.', $shop_version, 3);
+        $version_array = explode('.', $shop_version, 3);
+        if (count($version_array) < 2) {
+            // The format in _PS_VERSION_ has changed and it's unknown to us.
+            return [];
+
+        }
+        $major_version = current($version_array);
+        $minor_version = next($version_array);
 		return [
-			self::SHOP_SYSTEM             => 'prestashop',
-			self::SHOP_SYSTEM_VERSION     => $shop_version,
-			self::SHOP_SYSTEM_AND_VERSION => 'prestashop-' . $major_version . '.' . $minor_version,
+			self::$shop_system             => 'prestashop',
+			self::$shop_system_version     => $shop_version,
+			self::$shop_system_and_version => 'prestashop-' . $major_version . '.' . $minor_version,
 		];
 	}
 }
diff --git a/views/templates/admin/admin_help_buttons.tpl b/views/templates/admin/admin_help_buttons.tpl
index 0660fa2..d3f7118 100644
--- a/views/templates/admin/admin_help_buttons.tpl
+++ b/views/templates/admin/admin_help_buttons.tpl
@@ -10,5 +10,5 @@
 <div class="alert alert-info">
 <img src="../modules/wallee/logo.png" style="float:left; margin-right:15px;" height="50">
 <p><strong>{l s='This module requires an %s account.' sprintf='wallee' mod='wallee'}</strong></p>
-<p><a class="btn btn-default" href="https://app-wallee.com/user/signup" target="_blank">{l s='Sign Up' mod='wallee'}</a> <a class="btn btn-default" href="https://plugin-documentation.wallee.com/wallee-payment/prestashop-1.6/1.2.34/docs/en/documentation.html" target="_blank">{l s='Documentation' mod='wallee'}</a></p>
+<p><a class="btn btn-default" href="https://app-wallee.com/user/signup" target="_blank">{l s='Sign Up' mod='wallee'}</a> <a class="btn btn-default" href="https://plugin-documentation.wallee.com/wallee-payment/prestashop-1.6/1.2.36/docs/en/documentation.html" target="_blank">{l s='Documentation' mod='wallee'}</a></p>
 </div>
\ No newline at end of file
diff --git a/wallee.php b/wallee.php
index 3951b40..aed0744 100644
--- a/wallee.php
+++ b/wallee.php
@@ -34,7 +34,7 @@ public function __construct()
         $this->author = 'Customweb GmbH';
         $this->bootstrap = true;
         $this->need_instance = 0;
-        $this->version = '1.2.34';
+        $this->version = '1.2.36';
         $this->displayName = 'wallee';
         $this->description = $this->l('This PrestaShop module enables to process payments with %s.');
         $this->description = sprintf($this->description, 'wallee');