diff --git a/apps/impress/documentation.php b/apps/impress/documentation.php
index 5a153deb4c..1047262a67 100755
--- a/apps/impress/documentation.php
+++ b/apps/impress/documentation.php
@@ -24,7 +24,7 @@
 require_once('lib/impress.php');
 
 OCP\User::checkLoggedIn();
-OC_Util::checkAppEnabled('impress');
+OCP\JSON::checkAppEnabled('impress');
 OCP\App::setActiveNavigationEntry( 'impress_index' );
 
 
diff --git a/apps/impress/index.php b/apps/impress/index.php
index 59960ba96f..8648cb27e7 100755
--- a/apps/impress/index.php
+++ b/apps/impress/index.php
@@ -24,7 +24,7 @@
 require_once('lib/impress.php');
 
 OCP\User::checkLoggedIn();
-OC_Util::checkAppEnabled('impress');
+OCP\JSON::checkAppEnabled('impress');
 OCP\App::setActiveNavigationEntry( 'impress_index' );
 
 
diff --git a/apps/impress/player.php b/apps/impress/player.php
index 074badf5df..1f2423d856 100755
--- a/apps/impress/player.php
+++ b/apps/impress/player.php
@@ -25,7 +25,7 @@ require_once('lib/impress.php');
 
 // Check if we are a user
 OCP\User::checkLoggedIn();
-OC_Util::checkAppEnabled('impress');
+OCP\JSON::checkAppEnabled('impress');
 
 $filename = OCP\Util::sanitizeHTML($_GET['file']);
 $title = OCP\Util::sanitizeHTML($_GET['name']);