diff --git a/apps/user_ldap/tests/Integration/ExceptionOnLostConnection.php b/apps/user_ldap/tests/Integration/ExceptionOnLostConnection.php
index 32dfb72d9c..764c14bafe 100644
--- a/apps/user_ldap/tests/Integration/ExceptionOnLostConnection.php
+++ b/apps/user_ldap/tests/Integration/ExceptionOnLostConnection.php
@@ -96,7 +96,7 @@ class ExceptionOnLostConnection {
 	 */
 	public function setUp() {
 		require_once __DIR__  . '/../../../../lib/base.php';
-		\OC_App::loadApps('user_ldap');
+		\OC_App::loadApps(['user_ldap']);
 
 		$ch = $this->getCurl();
 		$proxyInfoJson = curl_exec($ch);
diff --git a/lib/private/Updater.php b/lib/private/Updater.php
index 43096e7c1f..727147e090 100644
--- a/lib/private/Updater.php
+++ b/lib/private/Updater.php
@@ -250,7 +250,7 @@ class Updater extends BasicEmitter {
 		$this->upgradeAppStoreApps(\OC::$server->getAppManager()->getInstalledApps());
 
 		// install new shipped apps on upgrade
-		OC_App::loadApps('authentication');
+		OC_App::loadApps(['authentication']);
 		$errors = Installer::installShippedApps(true);
 		foreach ($errors as $appId => $exception) {
 			/** @var \Exception $exception */
@@ -346,7 +346,7 @@ class Updater extends BasicEmitter {
 				if(!isset($stacks[$type])) {
 					$stacks[$type] = array();
 				}
-				if (\OC_App::isType($appId, $type)) {
+				if (\OC_App::isType($appId, [$type])) {
 					$stacks[$type][] = $appId;
 					$priorityType = true;
 					break;
diff --git a/lib/private/legacy/app.php b/lib/private/legacy/app.php
index c0794cdfa8..f04310041a 100644
--- a/lib/private/legacy/app.php
+++ b/lib/private/legacy/app.php
@@ -93,16 +93,16 @@ class OC_App {
 	/**
 	 * loads all apps
 	 *
-	 * @param string[] | string | null $types
+	 * @param string[] $types
 	 * @return bool
 	 *
 	 * This function walks through the ownCloud directory and loads all apps
 	 * it can find. A directory contains an app if the file /appinfo/info.xml
 	 * exists.
 	 *
-	 * if $types is set, only apps of those types will be loaded
+	 * if $types is set to non-empty array, only apps of those types will be loaded
 	 */
-	public static function loadApps($types = null) {
+	public static function loadApps(array $types = []): bool {
 		if (\OC::$server->getSystemConfig()->getValue('maintenance', false)) {
 			return false;
 		}
@@ -120,7 +120,7 @@ class OC_App {
 		// prevent app.php from printing output
 		ob_start();
 		foreach ($apps as $app) {
-			if ((is_null($types) or self::isType($app, $types)) && !in_array($app, self::$loadedApps)) {
+			if (($types === [] or self::isType($app, $types)) && !in_array($app, self::$loadedApps)) {
 				self::loadApp($app);
 			}
 		}
@@ -268,13 +268,10 @@ class OC_App {
 	 * check if an app is of a specific type
 	 *
 	 * @param string $app
-	 * @param string|array $types
+	 * @param array $types
 	 * @return bool
 	 */
-	public static function isType($app, $types) {
-		if (is_string($types)) {
-			$types = array($types);
-		}
+	public static function isType(string $app, array $types): bool {
 		$appTypes = self::getAppTypes($app);
 		foreach ($types as $type) {
 			if (array_search($type, $appTypes) !== false) {