diff --git a/modules/crossselling/crossselling.php b/modules/crossselling/crossselling.php
index ec157f73d..9381da964 100755
--- a/modules/crossselling/crossselling.php
+++ b/modules/crossselling/crossselling.php
@@ -43,9 +43,6 @@ class CrossSelling extends Module
 
 		$this->displayName = $this->l('Cross Selling');
 		$this->description = $this->l('Customers who bought this product also bought:');
-
-		if (!$this->isRegisteredInHook('header'))
-			$this->registerHook('header');
 	}
 
 	public function install()
diff --git a/modules/crossselling/upgrade/install-0.8.php b/modules/crossselling/upgrade/install-0.8.php
new file mode 100644
index 000000000..1ee79f5e5
--- /dev/null
+++ b/modules/crossselling/upgrade/install-0.8.php
@@ -0,0 +1,11 @@
+<?php
+
+if (!defined('_PS_VERSION_'))
+	exit;
+
+function upgrade_module_0_8($object)
+{
+	if (!$object->isRegisteredInHook('header'))
+		return $object->registerHook('header');
+	return true;
+}
diff --git a/modules/productscategory/productscategory.php b/modules/productscategory/productscategory.php
index 2210074ef..6290c5546 100644
--- a/modules/productscategory/productscategory.php
+++ b/modules/productscategory/productscategory.php
@@ -43,9 +43,6 @@ class productsCategory extends Module
 		
 		$this->displayName = $this->l('Products Category');
 		$this->description = $this->l('Display products of the same category on the product page.');
-		
-		if (!$this->isRegisteredInHook('header'))
-			$this->registerHook('header');
  	}
 
 	public function install()
diff --git a/modules/productscategory/upgrade/install-1.5.php b/modules/productscategory/upgrade/install-1.5.php
new file mode 100644
index 000000000..96e31c4c9
--- /dev/null
+++ b/modules/productscategory/upgrade/install-1.5.php
@@ -0,0 +1,11 @@
+<?php
+
+if (!defined('_PS_VERSION_'))
+	exit;
+
+function upgrade_module_1_5($object)
+{
+	if (!$object->isRegisteredInHook('header'))
+		return $object->registerHook('header');
+	return true;
+}