diff --git a/blackout/blackout.php b/blackout/blackout.php
index 68854200..c8574002 100644
--- a/blackout/blackout.php
+++ b/blackout/blackout.php
@@ -54,6 +54,7 @@ use Friendica\Core\Hook;
 use Friendica\Core\L10n;
 use Friendica\Core\Logger;
 use Friendica\Core\Renderer;
+use Friendica\Core\System;
 
 function blackout_install() {
     Hook::register('page_header', 'addon/blackout/blackout.php', 'blackout_redirect');
diff --git a/notifyall/notifyall.php b/notifyall/notifyall.php
index 51c426cc..58e54908 100644
--- a/notifyall/notifyall.php
+++ b/notifyall/notifyall.php
@@ -14,6 +14,7 @@ use Friendica\Core\Config;
 use Friendica\Core\L10n;
 use Friendica\Core\Logger;
 use Friendica\Core\Renderer;
+use Friendica\Core\System;
 use Friendica\Util\Emailer;
 
 function notifyall_install()
diff --git a/startpage/startpage.php b/startpage/startpage.php
index 82ae1eb0..0971818f 100644
--- a/startpage/startpage.php
+++ b/startpage/startpage.php
@@ -9,6 +9,7 @@
 use Friendica\Core\Hook;
 use Friendica\Core\L10n;
 use Friendica\Core\PConfig;
+use Friendica\Core\System;
 
 function startpage_install() {
 	Hook::register('home_init', 'addon/startpage/startpage.php', 'startpage_home_init');
diff --git a/statusnet/statusnet.php b/statusnet/statusnet.php
index 93fc874f..aba503a4 100644
--- a/statusnet/statusnet.php
+++ b/statusnet/statusnet.php
@@ -48,6 +48,7 @@ use Friendica\Core\Logger;
 use Friendica\Core\PConfig;
 use Friendica\Core\Protocol;
 use Friendica\Core\Renderer;
+use Friendica\Core\System;
 use Friendica\Database\DBA;
 use Friendica\Model\Contact;
 use Friendica\Model\GContact;
diff --git a/twitter/twitter.php b/twitter/twitter.php
index f05fc1f2..b1eeb5b8 100644
--- a/twitter/twitter.php
+++ b/twitter/twitter.php
@@ -75,6 +75,7 @@ use Friendica\Core\Logger;
 use Friendica\Core\PConfig;
 use Friendica\Core\Protocol;
 use Friendica\Core\Renderer;
+use Friendica\Core\System;
 use Friendica\Core\Worker;
 use Friendica\Database\DBA;
 use Friendica\Model\Contact;