diff --git a/mod/admin.php b/mod/admin.php
index 39a28158c..e3b537fcf 100644
--- a/mod/admin.php
+++ b/mod/admin.php
@@ -214,11 +214,12 @@ function admin_content(App $a)
 
 	$r = q("SELECT `name` FROM `addon` WHERE `plugin_admin` = 1 ORDER BY `name`");
 	$aside_tools['addons_admin'] = [];
+	$addons_admin = [];
 	foreach ($r as $h) {
 		$addon = $h['name'];
 		$aside_tools['addons_admin'][] = ["admin/addons/" . $addon, $addon, "addon"];
 		// temp addons with admin
-		$a->addons_admin[] = $addon;
+		$addons_admin[] = $addon;
 	}
 
 	$t = get_markup_template('admin/aside.tpl');
@@ -243,7 +244,7 @@ function admin_content(App $a)
 				$o = admin_page_users($a);
 				break;
 			case 'addons':
-				$o = admin_page_addons($a);
+				$o = admin_page_addons($a, $addons_admin);
 				break;
 			case 'themes':
 				$o = admin_page_themes($a);
@@ -932,7 +933,7 @@ function admin_page_summary(App $a)
 		'$platform' => FRIENDICA_PLATFORM,
 		'$codename' => FRIENDICA_CODENAME,
 		'$build' => Config::get('system', 'build'),
-		'$addons' => [L10n::t('Active addons'), $a->addons],
+		'$addons' => [L10n::t('Active addons'), Addon::getEnabledList()],
 		'$serversettings' => $server_settings,
 		'$showwarning' => $showwarning,
 		'$warningtext' => $warningtext
@@ -1956,10 +1957,11 @@ function admin_page_users(App $a)
  *
  * The returned string returned hulds the HTML code of the page.
  *
- * @param App $a
+ * @param App   $a
+ * @param array $addons_admin A list of admin addon names
  * @return string
  */
-function admin_page_addons(App $a)
+function admin_page_addons(App $a, array $addons_admin)
 {
 	/*
 	 * Single addon
@@ -1971,27 +1973,25 @@ function admin_page_addons(App $a)
 			return '';
 		}
 
-		if (x($_GET, "a") && $_GET['a'] == "t") {
+		if (defaults($_GET, 'a', '') == "t") {
 			BaseModule::checkFormSecurityTokenRedirectOnError('/admin/addons', 'admin_themes', 't');
 
 			// Toggle addon status
-			$idx = array_search($addon, $a->addons);
-			if ($idx !== false) {
-				unset($a->addons[$idx]);
+			if (Addon::isEnabled($addon)) {
 				Addon::uninstall($addon);
 				info(L10n::t("Addon %s disabled.", $addon));
 			} else {
-				$a->addons[] = $addon;
 				Addon::install($addon);
 				info(L10n::t("Addon %s enabled.", $addon));
 			}
-			Config::set("system", "addon", implode(", ", $a->addons));
+
+			Addon::saveEnabledList();
 			$a->internalRedirect('admin/addons');
 			return ''; // NOTREACHED
 		}
 
 		// display addon details
-		if (in_array($addon, $a->addons)) {
+		if (Addon::isEnabled($addon)) {
 			$status = "on";
 			$action = L10n::t("Disable");
 		} else {
@@ -2007,7 +2007,7 @@ function admin_page_addons(App $a)
 		}
 
 		$admin_form = "";
-		if (in_array($addon, $a->addons_admin)) {
+		if (in_array($addon, $addons_admin)) {
 			require_once "addon/$addon/$addon.php";
 			$func = $addon . '_addon_admin';
 			$func($a, $admin_form);
@@ -2058,7 +2058,7 @@ function admin_page_addons(App $a)
 				$show_addon = true;
 
 				// If the addon is unsupported, then only show it, when it is enabled
-				if ((strtolower($info["status"]) == "unsupported") && !in_array($id, $a->addons)) {
+				if ((strtolower($info["status"]) == "unsupported") && !Addon::isEnabled($id)) {
 					$show_addon = false;
 				}
 
@@ -2068,7 +2068,7 @@ function admin_page_addons(App $a)
 				}
 
 				if ($show_addon) {
-					$addons[] = [$id, (in_array($id, $a->addons) ? "on" : "off"), $info];
+					$addons[] = [$id, (Addon::isEnabled($id) ? "on" : "off"), $info];
 				}
 			}
 		}
diff --git a/mod/friendica.php b/mod/friendica.php
index f2cb5c50b..bf3f7942f 100644
--- a/mod/friendica.php
+++ b/mod/friendica.php
@@ -31,15 +31,7 @@ function friendica_init(App $a)
 			$admin = false;
 		}
 
-		$visible_addons = [];
-		if (is_array($a->addons) && count($a->addons)) {
-			$r = q("SELECT * FROM `addon` WHERE `hidden` = 0");
-			if (DBA::isResult($r)) {
-				foreach ($r as $rr) {
-					$visible_addons[] = $rr['name'];
-				}
-			}
-		}
+		$visible_addons = Addon::getVisibleList();
 
 		Config::load('feature_lock');
 		$locked_features = [];
@@ -91,16 +83,7 @@ function friendica_content(App $a)
 	$o .= L10n::t('Suggestions, praise, etc. - please email "info" at "friendi - dot - ca');
 	$o .= '</p>' . PHP_EOL;
 
-	$visible_addons = [];
-	if (is_array($a->addons) && count($a->addons)) {
-		$r = q("SELECT * FROM `addon` WHERE `hidden` = 0");
-		if (DBA::isResult($r)) {
-			foreach ($r as $rr) {
-				$visible_addons[] = $rr['name'];
-			}
-		}
-	}
-
+	$visible_addons = Addon::getVisibleList();
 	if (count($visible_addons)) {
 		$o .= '<p>' . L10n::t('Installed addons/apps:') . '</p>' . PHP_EOL;
 		$sorted = $visible_addons;
diff --git a/src/App.php b/src/App.php
index e312d8721..d8d6439d7 100644
--- a/src/App.php
+++ b/src/App.php
@@ -50,11 +50,8 @@ class App
 	public $argv;
 	public $argc;
 	public $module;
-	public $hooks = [];
 	public $timezone;
 	public $interactive = true;
-	public $addons;
-	public $addons_admin = [];
 	public $identities;
 	public $is_mobile = false;
 	public $is_tablet = false;
@@ -360,7 +357,7 @@ class App
 		Core\Config::load();
 
 		if ($this->getMode()->has(App\Mode::DBAVAILABLE)) {
-			Core\Addon::loadHooks();
+			Core\Hook::loadHooks();
 
 			$this->loadAddonConfig();
 		}
diff --git a/src/Core/Addon.php b/src/Core/Addon.php
index d2f89ce27..6b2d34170 100644
--- a/src/Core/Addon.php
+++ b/src/Core/Addon.php
@@ -16,7 +16,14 @@ require_once 'include/dba.php';
 class Addon extends BaseObject
 {
 	/**
-	 * @brief Synchronise addons:
+	 * List of the names of enabled addons
+	 *
+	 * @var array
+	 */
+	private static $addons = [];
+
+	/**
+	 * @brief Synchronize addons:
 	 *
 	 * system.addon contains a comma-separated list of names
 	 * of addons which are used on this system.
@@ -27,15 +34,13 @@ class Addon extends BaseObject
 	 * call the install procedure and add it to the database.
 	 *
 	 */
-	public static function check()
+	public static function loadAddons()
 	{
-		$a = self::getApp();
+		$installed_addons = [];
 
 		$r = DBA::select('addon', [], ['installed' => 1]);
 		if (DBA::isResult($r)) {
-			$installed = DBA::toArray($r);
-		} else {
-			$installed = [];
+			$installed_addons = DBA::toArray($r);
 		}
 
 		$addons = Config::get('system', 'addon');
@@ -45,31 +50,23 @@ class Addon extends BaseObject
 			$addons_arr = explode(',', str_replace(' ', '', $addons));
 		}
 
-		$a->addons = $addons_arr;
+		self::$addons = $addons_arr;
 
 		$installed_arr = [];
 
-		if (count($installed)) {
-			foreach ($installed as $i) {
-				if (!in_array($i['name'], $addons_arr)) {
-					self::uninstall($i['name']);
-				} else {
-					$installed_arr[] = $i['name'];
-				}
+		foreach ($installed_addons as $addon) {
+			if (!self::isEnabled($addon['name'])) {
+				self::uninstall($addon['name']);
+			} else {
+				$installed_arr[] = $addon['name'];
 			}
 		}
 
-		if (count($addons_arr)) {
-			foreach ($addons_arr as $p) {
-				if (!in_array($p, $installed_arr)) {
-					self::install($p);
-				}
+		foreach (self::$addons as $p) {
+			if (!in_array($p, $installed_arr)) {
+				self::install($p);
 			}
 		}
-
-		self::loadHooks();
-
-		return;
 	}
 
 	/**
@@ -88,6 +85,8 @@ class Addon extends BaseObject
 			$func = $addon . '_uninstall';
 			$func();
 		}
+
+		unset(self::$addons[$idx]);
 	}
 
 	/**
@@ -110,10 +109,10 @@ class Addon extends BaseObject
 			$func = $addon . '_install';
 			$func();
 
-			$addon_admin = (function_exists($addon."_addon_admin") ? 1 : 0);
+			$addon_admin = (function_exists($addon . "_addon_admin") ? 1 : 0);
 
 			DBA::insert('addon', ['name' => $addon, 'installed' => true,
-						'timestamp' => $t, 'plugin_admin' => $addon_admin]);
+				'timestamp' => $t, 'plugin_admin' => $addon_admin]);
 
 			// we can add the following with the previous SQL
 			// once most site tables have been updated.
@@ -122,6 +121,10 @@ class Addon extends BaseObject
 			if (file_exists('addon/' . $addon . '/.hidden')) {
 				DBA::update('addon', ['hidden' => true], ['name' => $addon]);
 			}
+
+			if (!self::isEnabled($addon)) {
+				self::$addons[] = $addon;
+			}
 			return true;
 		} else {
 			logger("Addons: FAILED installing " . $addon);
@@ -174,165 +177,6 @@ class Addon extends BaseObject
 		}
 	}
 
-	/**
-	 * @brief check if addon is enabled
-	 *
-	 * @param string $addon
-	 * @return boolean
-	 */
-	public static function isEnabled($addon)
-	{
-		return DBA::exists('addon', ['installed' => true, 'name' => $addon]);
-	}
-
-
-	/**
-	 * @brief registers a hook.
-	 *
-	 * @param string $hook the name of the hook
-	 * @param string $file the name of the file that hooks into
-	 * @param string $function the name of the function that the hook will call
-	 * @param int $priority A priority (defaults to 0)
-	 * @return mixed|bool
-	 */
-	public static function registerHook($hook, $file, $function, $priority = 0)
-	{
-		$file = str_replace(self::getApp()->getBasePath() . DIRECTORY_SEPARATOR, '', $file);
-
-		$condition = ['hook' => $hook, 'file' => $file, 'function' => $function];
-		$exists = DBA::exists('hook', $condition);
-		if ($exists) {
-			return true;
-		}
-
-		$r = DBA::insert('hook', ['hook' => $hook, 'file' => $file, 'function' => $function, 'priority' => $priority]);
-
-		return $r;
-	}
-
-	/**
-	 * @brief unregisters a hook.
-	 *
-	 * @param string $hook the name of the hook
-	 * @param string $file the name of the file that hooks into
-	 * @param string $function the name of the function that the hook called
-	 * @return array
-	 */
-	public static function unregisterHook($hook, $file, $function)
-	{
-		$relative_file = str_replace(self::getApp()->getBasePath() . DIRECTORY_SEPARATOR, '', $file);
-
-		// This here is only needed for fixing a problem that existed on the develop branch
-		$condition = ['hook' => $hook, 'file' => $file, 'function' => $function];
-		DBA::delete('hook', $condition);
-
-		$condition = ['hook' => $hook, 'file' => $relative_file, 'function' => $function];
-		$r = DBA::delete('hook', $condition);
-		return $r;
-	}
-
-	/**
-	 * Load hooks
-	 */
-	public static function loadHooks()
-	{
-		$a = self::getApp();
-		$a->hooks = [];
-		$r = DBA::select('hook', ['hook', 'file', 'function'], [], ['order' => ['priority' => 'desc', 'file']]);
-
-		while ($rr = DBA::fetch($r)) {
-			if (! array_key_exists($rr['hook'], $a->hooks)) {
-				$a->hooks[$rr['hook']] = [];
-			}
-			$a->hooks[$rr['hook']][] = [$rr['file'],$rr['function']];
-		}
-		DBA::close($r);
-	}
-
-	/**
-	 * @brief Forks a hook.
-	 *
-	 * Use this function when you want to fork a hook via the worker.
-	 *
-	 * @param string $name of the hook to call
-	 * @param string|array $data to transmit to the callback handler
-	 */
-	public static function forkHooks($priority, $name, $data = null)
-	{
-		$a = self::getApp();
-
-		if (is_array($a->hooks) && array_key_exists($name, $a->hooks)) {
-			foreach ($a->hooks[$name] as $hook) {
-				Worker::add($priority, 'ForkHook', $name, $hook, $data);
-			}
-		}
-	}
-
-	/**
-	 * @brief Calls a hook.
-	 *
-	 * Use this function when you want to be able to allow a hook to manipulate
-	 * the provided data.
-	 *
-	 * @param string $name of the hook to call
-	 * @param string|array &$data to transmit to the callback handler
-	 */
-	public static function callHooks($name, &$data = null)
-	{
-		$a = self::getApp();
-
-		if (is_array($a->hooks) && array_key_exists($name, $a->hooks)) {
-			foreach ($a->hooks[$name] as $hook) {
-				self::callSingleHook($a, $name, $hook, $data);
-			}
-		}
-	}
-
-	/**
-	 * @brief Calls a single hook.
-	 *
-	 * @param App $a
-	 * @param string         $name of the hook to call
-	 * @param array          $hook Hook data
-	 * @param string|array   &$data to transmit to the callback handler
-	 */
-	public static function callSingleHook(App $a, $name, $hook, &$data = null)
-	{
-		// Don't run a theme's hook if the user isn't using the theme
-		if (strpos($hook[0], 'view/theme/') !== false && strpos($hook[0], 'view/theme/' . $a->getCurrentTheme()) === false) {
-			return;
-		}
-
-		@include_once($hook[0]);
-		if (function_exists($hook[1])) {
-			$func = $hook[1];
-			$func($a, $data);
-		} else {
-			// remove orphan hooks
-			$condition = ['hook' => $name, 'file' => $hook[0], 'function' => $hook[1]];
-			DBA::delete('hook', $condition, ['cascade' => false]);
-		}
-	}
-
-	/**
-	 * check if an app_menu hook exist for addon $name.
-	 * Return true if the addon is an app
-	 */
-	public static function isApp($name)
-	{
-		$a = self::getApp();
-
-		if (is_array($a->hooks) && (array_key_exists('app_menu', $a->hooks))) {
-			foreach ($a->hooks['app_menu'] as $hook) {
-				if ($hook[0] == 'addon/'.$name.'/'.$name.'.php') {
-					return true;
-				}
-			}
-		}
-
-		return false;
-	}
-
 	/**
 	 * @brief Parse addon comment in search of addon infos.
 	 *
@@ -401,4 +245,92 @@ class Addon extends BaseObject
 		}
 		return $info;
 	}
+
+	/**
+	 * Checks if the provided addon is enabled
+	 *
+	 * @param string $addon
+	 * @return boolean
+	 */
+	public static function isEnabled($addon)
+	{
+		return in_array($addon, self::$addons);
+	}
+
+	public static function getEnabledList()
+	{
+		return self::$addons;
+	}
+
+	/**
+	 * Saves the current enabled addon list in the system.addon config key
+	 *
+	 * @return boolean
+	 */
+	public static function saveEnabledList()
+	{
+		return Config::set("system", "addon", implode(", ", self::$addons));
+	}
+
+	/**
+	 * Returns the list of non-hidden enabled addon names
+	 *
+	 * @return array
+	 */
+	public static function getVisibleList()
+	{
+		$visible_addons = [];
+		$stmt = DBA::select('addon', ['name'], ['hidden' => false, 'installed' => true]);
+		if (DBA::isResult($stmt)) {
+			foreach (DBA::toArray($stmt) as $addon) {
+				$visible_addons[] = $addon['name'];
+			}
+		}
+
+		return $visible_addons;
+	}
+
+	/**
+	 * Shim of Hook::register left for backward compatibility purpose.
+	 *
+	 * @see Hook::register
+	 * @deprecated since version 2018.12
+	 * @param string $hook     the name of the hook
+	 * @param string $file     the name of the file that hooks into
+	 * @param string $function the name of the function that the hook will call
+	 * @param int    $priority A priority (defaults to 0)
+	 * @return mixed|bool
+	 */
+	public static function registerHook($hook, $file, $function, $priority = 0)
+	{
+		return Hook::register($hook, $file, $function, $priority);
+	}
+
+	/**
+	 * Shim of Hook::unregister left for backward compatibility purpose.
+	 *
+	 * @see Hook::unregister
+	 * @deprecated since version 2018.12
+	 * @param string $hook     the name of the hook
+	 * @param string $file     the name of the file that hooks into
+	 * @param string $function the name of the function that the hook called
+	 * @return boolean
+	 */
+	public static function unregisterHook($hook, $file, $function)
+	{
+		return Hook::unregister($hook, $file, $function);
+	}
+
+	/**
+	 * Shim of Hook::callAll left for backward-compatibility purpose.
+	 *
+	 * @see Hook::callAll
+	 * @deprecated since version 2018.12
+	 * @param string       $name  of the hook to call
+	 * @param string|array &$data to transmit to the callback handler
+	 */
+	public static function callHooks($name, &$data = null)
+	{
+		Hook::callAll($name, $data);
+	}
 }
diff --git a/src/Object/Post.php b/src/Object/Post.php
index 70428ab84..85d7a3b8c 100644
--- a/src/Object/Post.php
+++ b/src/Object/Post.php
@@ -771,7 +771,7 @@ class Post extends BaseObject
 			 * Hmmm, code depending on the presence of a particular addon?
 			 * This should be better if done by a hook
 			 */
-			if (in_array('qcomment', $a->addons)) {
+			if (Addon::isEnabled('qcomment')) {
 				$qc = ((local_user()) ? PConfig::get(local_user(), 'qcomment', 'words') : null);
 				$qcomment = (($qc) ? explode("\n", $qc) : null);
 			}
diff --git a/src/Worker/Cron.php b/src/Worker/Cron.php
index b6dd896cd..54e6cb676 100644
--- a/src/Worker/Cron.php
+++ b/src/Worker/Cron.php
@@ -7,6 +7,7 @@ namespace Friendica\Worker;
 use Friendica\BaseObject;
 use Friendica\Core\Addon;
 use Friendica\Core\Config;
+use Friendica\Core\Hook;
 use Friendica\Core\Protocol;
 use Friendica\Core\Worker;
 use Friendica\Database\DBA;
@@ -45,7 +46,7 @@ class Cron
 		logger('cron: start');
 
 		// Fork the cron jobs in separate parts to avoid problems when one of them is crashing
-		Addon::forkHooks($a->queue['priority'], "cron");
+		Hook::fork($a->queue['priority'], "cron");
 
 		// run queue delivery process in the background
 		Worker::add(PRIORITY_NEGLIGIBLE, "Queue");
diff --git a/src/Worker/Expire.php b/src/Worker/Expire.php
index b6096b584..de2133bdc 100644
--- a/src/Worker/Expire.php
+++ b/src/Worker/Expire.php
@@ -7,8 +7,8 @@
 namespace Friendica\Worker;
 
 use Friendica\BaseObject;
-use Friendica\Core\Addon;
 use Friendica\Core\Config;
+use Friendica\Core\Hook;
 use Friendica\Core\Worker;
 use Friendica\Database\DBA;
 use Friendica\Model\Item;
@@ -17,13 +17,13 @@ require_once 'include/dba.php';
 
 class Expire
 {
-	public static function execute($param = '', $hook_name = '')
+	public static function execute($param = '', $hook_function = '')
 	{
 		$a = BaseObject::getApp();
 
 		require_once 'include/items.php';
 
-		Addon::loadHooks();
+		Hook::loadHooks();
 
 		if ($param == 'delete') {
 			logger('Delete expired items', LOGGER_DEBUG);
@@ -62,11 +62,11 @@ class Expire
 				logger('Expire items for user '.$user['uid'].' ('.$user['username'].') - done ', LOGGER_DEBUG);
 			}
 			return;
-		} elseif (!empty($hook_name) && ($param == 'hook') && is_array($a->hooks) && array_key_exists("expire", $a->hooks)) {
-			foreach ($a->hooks["expire"] as $hook) {
-				if ($hook[1] == $hook_name) {
+		} elseif ($param == 'hook' && !empty($hook_function)) {
+			foreach (Hook::getByName('expire') as $hook) {
+				if ($hook[1] == $hook_function) {
 					logger("Calling expire hook '" . $hook[1] . "'", LOGGER_DEBUG);
-					Addon::callSingleHook($a, $hook_name, $hook, $data);
+					Hook::callSingle($a, 'expire', $hook, $data);
 				}
 			}
 			return;
@@ -86,13 +86,10 @@ class Expire
 		DBA::close($r);
 
 		logger('expire: calling hooks');
-
-		if (is_array($a->hooks) && array_key_exists('expire', $a->hooks)) {
-			foreach ($a->hooks['expire'] as $hook) {
-				logger("Calling expire hook for '" . $hook[1] . "'", LOGGER_DEBUG);
-				Worker::add(['priority' => $a->queue['priority'], 'created' => $a->queue['created'], 'dont_fork' => true],
-						'Expire', 'hook', $hook[1]);
-			}
+		foreach (Hook::getByName('expire') as $hook) {
+			logger("Calling expire hook for '" . $hook[1] . "'", LOGGER_DEBUG);
+			Worker::add(['priority' => $a->queue['priority'], 'created' => $a->queue['created'], 'dont_fork' => true],
+					'Expire', 'hook', $hook[1]);
 		}
 
 		logger('expire: end');
diff --git a/src/Worker/ForkHook.php b/src/Worker/ForkHook.php
index 3654bdd3c..586d1496e 100644
--- a/src/Worker/ForkHook.php
+++ b/src/Worker/ForkHook.php
@@ -5,7 +5,7 @@
 
 namespace Friendica\Worker;
 
-use Friendica\Core\Addon;
+use Friendica\Core\Hook;
 
 Class ForkHook
 {
@@ -13,6 +13,6 @@ Class ForkHook
 	{
 		$a = \Friendica\BaseObject::getApp();
 
-		Addon::callSingleHook($a, $name, $hook, $data);
+		Hook::callSingle($a, $name, $hook, $data);
 	}
 }
diff --git a/src/Worker/Notifier.php b/src/Worker/Notifier.php
index 3edc15c3b..31000a26f 100644
--- a/src/Worker/Notifier.php
+++ b/src/Worker/Notifier.php
@@ -7,10 +7,12 @@ namespace Friendica\Worker;
 use Friendica\BaseObject;
 use Friendica\Core\Addon;
 use Friendica\Core\Config;
+use Friendica\Core\Hook;
 use Friendica\Core\Protocol;
 use Friendica\Core\Worker;
 use Friendica\Database\DBA;
 use Friendica\Model\Contact;
+use Friendica\Model\Conversation;
 use Friendica\Model\Group;
 use Friendica\Model\Item;
 use Friendica\Model\PushSubscriber;
@@ -20,7 +22,6 @@ use Friendica\Protocol\ActivityPub;
 use Friendica\Protocol\Diaspora;
 use Friendica\Protocol\OStatus;
 use Friendica\Protocol\Salmon;
-use Friendica\Model\Conversation;
 
 require_once 'include/dba.php';
 require_once 'include/items.php';
@@ -501,7 +502,7 @@ class Notifier
 		logger('notifier: calling hooks for ' . $cmd . ' ' . $item_id, LOGGER_DEBUG);
 
 		if ($normal_mode) {
-			Addon::forkHooks($a->queue['priority'], 'notifier_normal', $target_item);
+			Hook::fork($a->queue['priority'], 'notifier_normal', $target_item);
 		}
 
 		Addon::callHooks('notifier_end',$target_item);