diff --git a/src/private/php/AdminStatus.php b/src/private/php/AdminStatus.php
index 92d6ee0..5580e9f 100644
--- a/src/private/php/AdminStatus.php
+++ b/src/private/php/AdminStatus.php
@@ -15,16 +15,16 @@ class AdminStatus {
 
     private $cache;
 
-    const STATUS_STYLE_GROUPED = 1;
-    const STATUS_STYLE_GROUPED_HIDE_EMPTY_GROUPS = 2;
-    const STATUS_STYLE_LIST = 3;
-    const STATUS_STYLE_LIST_ONLINE_FIRST = 4;
+    public const STATUS_STYLE_GROUPED = 1;
+    public const STATUS_STYLE_GROUPED_HIDE_EMPTY_GROUPS = 2;
+    public const STATUS_STYLE_LIST = 3;
+    public const STATUS_STYLE_LIST_ONLINE_FIRST = 4;
 
     public function __construct() {
         $this->cache = new PhpFileCache(__CACHE_DIR, "adminstatus");
     }
 
-    public function getCachedAdminClients(array $adminGroups) {
+    public function getCachedAdminClients(array $adminGroups): ?array {
         return $this->cache->refreshIfExpired("adminstatus", function () use ($adminGroups) {
             if(TeamSpeakUtils::i()->checkTSConnection()) {
                 try {
@@ -44,7 +44,7 @@ class AdminStatus {
         }, Config::get("cache_adminstatus"));
     }
 
-    public function getStatus(array $adminGroups, $format, $hideOffline = false, array $ignoredUsersDbids = []) {
+    public function getStatus(array $adminGroups, $format, bool $hideOffline = false, array $ignoredUsersDbids = []) {
         if ($format !== self::STATUS_STYLE_GROUPED
             && $format !== self::STATUS_STYLE_GROUPED_HIDE_EMPTY_GROUPS
             && $format !== self::STATUS_STYLE_LIST
diff --git a/src/private/php/Assigner.php b/src/private/php/Assigner.php
index 85236fc..6d28ee6 100644
--- a/src/private/php/Assigner.php
+++ b/src/private/php/Assigner.php
@@ -6,11 +6,11 @@ use Wruczek\TSWebsite\Utils\TeamSpeakUtils;
 
 class Assigner {
 
-    public static function getAssignerConfig() {
+    public static function getAssignerConfig(): array {
         return Config::get("assignerconfig");
     }
 
-    public static function getAssignerArray() {
+    public static function getAssignerArray(): array {
         $assignerConfig = self::getAssignerConfig();
 
         if (empty($assignerConfig)) {
@@ -46,7 +46,7 @@ class Assigner {
         return $assignerConfig;
     }
 
-    public static function isAssignable($sgid) {
+    public static function isAssignable(int $sgid): bool {
         foreach (self::getAssignerConfig() as $category) {
             if (in_array($sgid, $category["groups"], true)) {
                 return true;
@@ -69,7 +69,7 @@ class Assigner {
      * @throws UserNotAuthenticatedException
      * @throws \TeamSpeak3_Exception
      */
-    public static function changeGroups($newGroups) {
+    public static function changeGroups(array $newGroups): int {
         $assignerConfig = self::getAssignerConfig();
 
         if (empty($assignerConfig)) {
@@ -85,9 +85,9 @@ class Assigner {
 
             foreach ($config["groups"] as $group) {
                 // true if the $group is currently assigned to the user
-                $isAssigned = in_array($group, $userGroups);
+                $isAssigned = in_array($group, $userGroups, true);
                 // true if the user wants to be added to $group
-                $wantToAssign = in_array($group, $newGroups);
+                $wantToAssign = in_array($group, $newGroups, true);
 
                 // if the group is already assigned, or is to be assigned,
                 // check for the max group limit in this category:
@@ -133,11 +133,11 @@ class Assigner {
         return 0;
     }
 
-    public static function getRequiredSgids() {
+    public static function getRequiredSgids(): array {
         return Config::get("assigner_required_sgids");
     }
 
-    public static function canUseAssigner() {
+    public static function canUseAssigner(): bool {
         // if there are no required sgids, the user can use assigner and
         // we can skip the other, more expensive checks that will require
         // fetching user groups from TS3
@@ -149,7 +149,7 @@ class Assigner {
         return self::canUseAssignerSgArray($userGroups);
     }
 
-    public static function canUseAssignerSgArray(array $serverGroups) {
+    public static function canUseAssignerSgArray(array $serverGroups): bool {
         // user needs to be in at least one of those groups to be able
         // to use group assigner
         $requiredSgid = self::getRequiredSgids();
diff --git a/src/private/php/Auth.php b/src/private/php/Auth.php
index 8df7f9e..20eb898 100644
--- a/src/private/php/Auth.php
+++ b/src/private/php/Auth.php
@@ -10,26 +10,26 @@ use Wruczek\TSWebsite\Utils\Utils;
 class Auth {
 
     public static function isLoggedIn() {
-        return !empty(self::getCldbid()) && !empty(self::getUid());
+        return self::getCldbid() !== null && self::getUid() !== null;
     }
 
-    public static function getUid() {
+    public static function getUid(): ?string {
         return @$_SESSION["tsuser"]["uid"];
     }
 
-    public static function getCldbid() {
+    public static function getCldbid(): ?int {
         return @$_SESSION["tsuser"]["cldbid"];
     }
 
-    public static function getNickname() {
+    public static function getNickname(): ?string {
         return @$_SESSION["tsuser"]["nickname"];
     }
 
-    public static function logout() {
+    public static function logout(): void {
         unset($_SESSION["tsuser"]);
     }
 
-    public static function getTsUsersByIp($ip = null) {
+    public static function getTsUsersByIp(string $ip = null): ?array {
         if ($ip === null) {
             $ip = Utils::getClientIp();
         }
@@ -62,7 +62,7 @@ class Auth {
      * @param $ip string optional, defaults to Utils::getClientIp
      * @return bool true if the cldbid have the same IP address as $ip
      */
-    public static function checkClientIp($cldbid, $ip = null) {
+    public static function checkClientIp(int $cldbid, string $ip = null): bool {
         if ($ip === null) {
             $ip = Utils::getClientIp();
         }
@@ -84,7 +84,7 @@ class Auth {
      *         client cannot be found and false when other error occurs.
      * @throws \TeamSpeak3_Adapter_ServerQuery_Exception
      */
-    public static function generateConfirmationCode($cldbid, $poke = null) {
+    public static function generateConfirmationCode(int $cldbid, ?bool $poke = null) {
         if ($poke === null) {
             $poke = (bool) Config::get("loginpokeclient");
         }
@@ -123,7 +123,7 @@ class Auth {
      * @param $cldbid int
      * @return string|null Confirmation code, null if not found
      */
-    public static function getConfirmationCode($cldbid) {
+    public static function getConfirmationCode(int $cldbid): ?string {
         return (new PhpFileCache(__CACHE_DIR, "confirmationcodes"))->retrieve("c_$cldbid");
     }
 
@@ -132,7 +132,7 @@ class Auth {
      * @param $cldbid int
      * @param $code string
      */
-    public static function saveConfirmationCode($cldbid, $code) {
+    public static function saveConfirmationCode(int $cldbid, string $code): void {
         (new PhpFileCache(__CACHE_DIR, "confirmationcodes"))->store("c_$cldbid", $code, (int) Config::get("cache_logincode"));
     }
 
@@ -140,7 +140,7 @@ class Auth {
      * Deletes confirmation code for the user
      * @param $cldbid int
      */
-    public static function deleteConfirmationCode($cldbid) {
+    public static function deleteConfirmationCode(int $cldbid): void {
         (new PhpFileCache(__CACHE_DIR, "confirmationcodes"))->eraseKey("c_$cldbid");
     }
 
@@ -150,7 +150,7 @@ class Auth {
      * @param $userCode
      * @return bool true if authentication was successful
      */
-    public static function checkCodeAndLogin($cldbid, $userCode) {
+    public static function checkCodeAndLogin(int $cldbid, string $userCode): bool {
         if (!is_int($cldbid)) {
             throw new \InvalidArgumentException("cldbid must be an int");
         }
@@ -176,7 +176,7 @@ class Auth {
      * @param $userCode string
      * @return bool
      */
-    public static function checkConfirmationCode($cldbid, $userCode) {
+    public static function checkConfirmationCode(int $cldbid, string $userCode): bool {
         $knownCode = self::getConfirmationCode($cldbid);
 
         if ($knownCode === null) {
@@ -191,7 +191,7 @@ class Auth {
      * @param $cldbid int
      * @return bool true on success, false otherwise
      */
-    public static function loginUser($cldbid) {
+    public static function loginUser(int $cldbid): bool {
         $clientList = CacheManager::i()->getClientList();
 
         foreach ($clientList as $client) {
@@ -206,18 +206,18 @@ class Auth {
         return false;
     }
 
-    public static function invalidateUserGroupCache() {
+    public static function invalidateUserGroupCache(): void {
         unset($_SESSION["tsuser"]["servergroups"]);
     }
 
     /**
      * Returns an array containing cached array with group IDs of the user
      * @param $cacheTime int for how long we should cache the IDs?
-     * @return array array with server group IDs of the user
+     * @return array array with server group IDs of the user as ints
      * @throws UserNotAuthenticatedException if user is not logged in
      * @throws \TeamSpeak3_Exception when we cannot get data from the TS server
      */
-    public static function getUserServerGroupIds($cacheTime = 60) {
+    public static function getUserServerGroupIds(int $cacheTime = 60): array {
         if (!self::isLoggedIn()) {
             throw new UserNotAuthenticatedException("User is not authenticated");
         }
@@ -273,17 +273,15 @@ class Auth {
      * @throws UserNotAuthenticatedException if user is not logged in
      * @throws \TeamSpeak3_Exception when we cannot get data from the TS server
      */
-    public static function getUserServerGroups($cacheTime = 60) {
+    public static function getUserServerGroups(int $cacheTime = 60): array {
         $serverGroupIds = self::getUserServerGroupIds($cacheTime);
         $serverGroups = CacheManager::i()->getServerGroupList();
 
-        $resut = array_filter($serverGroups, function ($serverGroup) use ($serverGroupIds) {
+        return array_filter($serverGroups, function (array $serverGroup) use ($serverGroupIds) {
             // If the group id is inside $serverGroupIds,
             // keep that group. Otherwise filter it out.
-            return in_array($serverGroup["sgid"], $serverGroupIds);
+            return in_array($serverGroup["sgid"], $serverGroupIds, true);
         });
-
-        return $resut;
     }
 }
 
diff --git a/src/private/php/CacheManager.php b/src/private/php/CacheManager.php
index fa5b9b4..41686d4 100644
--- a/src/private/php/CacheManager.php
+++ b/src/private/php/CacheManager.php
@@ -7,6 +7,7 @@ use Wruczek\TSWebsite\Utils\SingletonTait;
 use Wruczek\TSWebsite\Utils\TeamSpeakUtils;
 
 class CacheManager {
+
     use SingletonTait;
 
     private $cache;
@@ -22,11 +23,7 @@ class CacheManager {
         $this->cache = new PhpFileCache(__CACHE_DIR, "cachemanager");
     }
 
-    private function tsNodeObjectToArray(array $object, $extendInfo = false) {
-        if (!is_array($object)) {
-            throw new \Exception("object must be a array filled with TeamSpeak3_Node_Abstract objects");
-        }
-
+    private function tsNodeObjectToArray(array $object, bool $extendInfo = false): array {
         $data = [];
 
         foreach ($object as $obj) {
@@ -36,7 +33,7 @@ class CacheManager {
         return $data;
     }
 
-    public function getServerInfo($meta = false) {
+    public function getServerInfo(bool $meta = false) {
         if ($this->serverInfo) {
             return $this->serverInfo;
         }
@@ -49,15 +46,16 @@ class CacheManager {
                     TeamSpeakUtils::i()->addExceptionToExceptionsList($e);
                 }
             }
+
             return null;
         }, Config::get("cache_serverinfo"), $meta);
     }
 
-    public function clearServerInfo() {
+    public function clearServerInfo(): void {
         $this->cache->eraseKey("serverinfo");
     }
 
-    public function getBanList($meta = false) {
+    public function getBanList(bool $meta = false) {
         if ($this->banList) {
             return $this->banList;
         }
@@ -74,15 +72,16 @@ class CacheManager {
                     TeamSpeakUtils::i()->addExceptionToExceptionsList($e);
                 }
             }
+
             return null;
         }, Config::get("cache_banlist"), $meta);
     }
 
-    public function clearBanList() {
+    public function clearBanList(): void {
         $this->cache->eraseKey("banlist");
     }
 
-    public function getClientList($meta = false) {
+    public function getClientList(bool $meta = false) {
         if ($this->clientList) {
             return $this->clientList;
         }
@@ -95,15 +94,16 @@ class CacheManager {
                     TeamSpeakUtils::i()->addExceptionToExceptionsList($e);
                 }
             }
+
             return null;
         }, Config::get("cache_clientlist"), $meta); // Lower cache time because of login system
     }
 
-    public function clearClientList() {
+    public function clearClientList(): void {
         $this->cache->eraseKey("clientlist");
     }
 
-    public function getClient($cldbid) {
+    public function getClient(int $cldbid) {
         $clients = $this->getClientList();
 
         if ($clients === null) {
@@ -119,7 +119,7 @@ class CacheManager {
         return null;
     }
 
-    public function getChannelList($meta = false) {
+    public function getChannelList(bool $meta = false) {
         if ($this->channelList) {
             return $this->channelList;
         }
@@ -132,15 +132,16 @@ class CacheManager {
                     TeamSpeakUtils::i()->addExceptionToExceptionsList($e);
                 }
             }
+
             return null;
         }, Config::get("cache_channelist"), $meta);
     }
 
-    public function clearChannelList() {
+    public function clearChannelList(): void {
         $this->cache->eraseKey("channellist");
     }
 
-    public function getServerGroupList($meta = false) {
+    public function getServerGroupList(bool $meta = false) {
         if ($this->serverGroupList) {
             return $this->serverGroupList;
         }
@@ -153,15 +154,16 @@ class CacheManager {
                     TeamSpeakUtils::i()->addExceptionToExceptionsList($e);
                 }
             }
+
             return null;
         }, Config::get("cache_servergroups"), $meta);
     }
 
-    public function clearServerGroupList() {
+    public function clearServerGroupList(): void {
         $this->cache->eraseKey("servergrouplist");
     }
 
-    public function getChannelGroupList($meta = false) {
+    public function getChannelGroupList(bool $meta = false) {
         if ($this->channelGroupList) {
             return $this->channelGroupList;
         }
@@ -174,11 +176,12 @@ class CacheManager {
                     TeamSpeakUtils::i()->addExceptionToExceptionsList($e);
                 }
             }
+
             return null;
         }, Config::get("cache_channelgroups"), $meta);
     }
 
-    public function clearChannelGroupList() {
+    public function clearChannelGroupList(): void {
         $this->cache->eraseKey("channelgrouplist");
     }
 }
diff --git a/src/private/php/News/DefaultNewsStore.php b/src/private/php/News/DefaultNewsStore.php
index 9272309..1b314a7 100644
--- a/src/private/php/News/DefaultNewsStore.php
+++ b/src/private/php/News/DefaultNewsStore.php
@@ -2,8 +2,6 @@
 
 namespace Wruczek\TSWebsite\News;
 
-use function mb_substr;
-use function time;
 use Wruczek\TSWebsite\Utils\DatabaseUtils;
 
 /**
@@ -20,15 +18,7 @@ class DefaultNewsStore implements INewsStore {
         $this->db = DatabaseUtils::i()->getDb();
     }
 
-    public function getNewsList($limit, $offset = null) {
-        if ($limit !== null && !\is_int($limit)) {
-            throw new \InvalidArgumentException("limit must be an integer");
-        }
-
-        if ($offset !== null && !\is_int($offset)) {
-            throw new \InvalidArgumentException("offset must be an integer");
-        }
-
+    public function getNewsList(int $limit, int $offset = null): array {
         $options = []; // Medoo: [$offset, $limit]
 
         // If we have both limit and offset
@@ -64,17 +54,17 @@ class DefaultNewsStore implements INewsStore {
         return $newsList;
     }
 
-    public function getNews($newsId) {
+    public function getNews(int $newsId): ?array {
         return $this->db->get($this->newsTable, "*", [
             "newsId" => $newsId,
         ]);
     }
 
-    public function getNewsCount() {
+    public function getNewsCount(): int {
         return $this->db->count($this->newsTable);
     }
 
-    public function addNews($title, $content, $addDate = null, $editDate = null) {
+    public function addNews(string $title, string $content, ?int $addDate = null, ?int $editDate = null): int {
         if ($addDate === null) {
             $addDate = time();
         }
@@ -89,7 +79,7 @@ class DefaultNewsStore implements INewsStore {
         return $this->db->id();
     }
 
-    public function editNews($newsId, $title = null, $content = null, $addDate = null, $editDate = null) {
+    public function editNews(int $newsId, string $title = null, string $content = null, ?int $addDate = null, ?int $editDate = null): bool {
         $data = [];
 
         if ($title !== null) $data["title"] = $title;
diff --git a/src/private/php/News/INewsStore.php b/src/private/php/News/INewsStore.php
index 0da7e98..6382556 100644
--- a/src/private/php/News/INewsStore.php
+++ b/src/private/php/News/INewsStore.php
@@ -24,20 +24,20 @@ interface INewsStore {
      * @return array array with the news
      * @throws \Exception when we cannot get the news
      */
-    public function getNewsList($limit, $offset = null);
+    public function getNewsList(int $limit, int $offset = null): array;
 
     /**
      * Returns full information about this particular news
      * @param int $newsId
      * @return array|null array with the news details or null if news was not found
      */
-    public function getNews($newsId);
+    public function getNews(int $newsId): ?array;
 
     /**
      * Returns a number of news in the database
      * @return int
      */
-    public function getNewsCount();
+    public function getNewsCount(): int;
 
     /**
      * Adds a new news and return its new id
@@ -47,7 +47,7 @@ interface INewsStore {
      * @param null|int $editDate
      * @return int newsId of the inserted news
      */
-    public function addNews($title, $content, $addDate = null, $editDate = null);
+    public function addNews(string $title, string $content, ?int $addDate = null, ?int $editDate = null): int;
 
     /**
      * Edit the news selected by $newsId. All parameters are optional, and only the provided ones will be changed
@@ -56,7 +56,8 @@ interface INewsStore {
      * @param string|null $content
      * @param int|null $addDate
      * @param int|null $editDate
+     * @return bool true on success
      */
-    public function editNews($newsId, $title = null, $content = null, $addDate = null, $editDate = null);
+    public function editNews(int $newsId, string $title = null, string $content = null, ?int $addDate = null, ?int $editDate = null): bool;
 
 }
diff --git a/src/private/php/ServerIconCache.php b/src/private/php/ServerIconCache.php
index 141bf7d..9147df0 100644
--- a/src/private/php/ServerIconCache.php
+++ b/src/private/php/ServerIconCache.php
@@ -9,20 +9,32 @@ class ServerIconCache {
 
     private static $iconsCacheDir = __CACHE_DIR . "/servericons";
 
-    public static function getIconBytes($iconId) {
+    /**
+     * Returns contents of an icon
+     * @param string|int $iconId icon id
+     * @return string|null returns contents as string or null if not found
+     * @throws \Exception
+     */
+    public static function getIconBytes($iconId): ?string {
         if (!is_numeric($iconId)) {
             throw new \Exception("iconid need to be an int or numeric string");
         }
 
         $file = @file_get_contents(self::$iconsCacheDir . "/" . $iconId);
-        return $file === false ? null : $file; // return null on error
+
+        // return null on error
+        if ($file === false) {
+            return null;
+        }
+
+        return $file;
     }
 
-    public static function hasIcon($iconId) {
+    public static function hasIcon($iconId): bool {
         return self::getIconBytes($iconId) !== null;
     }
 
-    public static function syncIcons() {
+    public static function syncIcons(): void {
         if (!file_exists(self::$iconsCacheDir) && !mkdir(self::$iconsCacheDir)) {
             throw new \Exception("Cannot create icons cache directory at " . self::$iconsCacheDir);
         }
@@ -36,7 +48,7 @@ class ServerIconCache {
             }
 
             try {
-                $iconData = self::downloadIcon($iconId);
+                $iconData = (string) self::downloadIcon($iconId);
             } catch (\Exception $e) {
                 trigger_error("Cannot download icon $iconId");
                 continue;
@@ -50,7 +62,7 @@ class ServerIconCache {
         }
     }
 
-    public static function syncIfNeeded() {
+    public static function syncIfNeeded(): void {
         (new PhpFileCache(__CACHE_DIR))->refreshIfExpired("lasticonsync", function () {
             // Do not sync icons if we cannot connect the the TS server
             if (!TeamSpeakUtils::i()->checkTSConnection()) {
@@ -62,11 +74,11 @@ class ServerIconCache {
         }, Config::get("cache_servericons", 300));
     }
 
-    public static function isLocal($iconId) {
+    public static function isLocal(int $iconId): bool {
         return $iconId > 0 && $iconId < 1000;
     }
 
-    public static function iconIdFromName($iconName) {
+    public static function iconIdFromName(string $iconName): string {
         return substr($iconName, 5);
     }
 
@@ -78,7 +90,7 @@ class ServerIconCache {
      * @param $iconId int
      * @return int
      */
-    public static function unsignIcon($iconId) {
+    public static function unsignIcon(int $iconId): int {
         if (!is_int($iconId)) {
             throw new \InvalidArgumentException("iconId must be an integer");
         }
@@ -86,11 +98,11 @@ class ServerIconCache {
         return ($iconId < 0) ? (2 ** 32) - ($iconId * -1) : $iconId;
     }
 
-    public static function downloadIcon($iconId) {
+    public static function downloadIcon($iconId): \TeamSpeak3_Helper_String {
         return TeamSpeakUtils::i()->ftDownloadFile("/icon_$iconId");
     }
 
-    public static function ftDownloadIconList() {
+    public static function ftDownloadIconList(): array {
         try {
             return TeamSpeakUtils::i()->getTSNodeServer()->channelFileList(0, "", "/icons/");
         } catch (\TeamSpeak3_Adapter_ServerQuery_Exception $e) {
diff --git a/src/private/php/Utils/ApiUtils.php b/src/private/php/Utils/ApiUtils.php
index f20b68b..f15d7e9 100644
--- a/src/private/php/Utils/ApiUtils.php
+++ b/src/private/php/Utils/ApiUtils.php
@@ -2,7 +2,6 @@
 
 namespace Wruczek\TSWebsite\Utils;
 
-use function is_array;
 use Wruczek\TSWebsite\Auth;
 
 class ApiUtils {
@@ -10,7 +9,7 @@ class ApiUtils {
     /**
      * Checks if the user is logged in, and if not outputs a JSON error and terminates the script
      */
-    public static function checkAuth() {
+    public static function checkAuth(): void {
         if (!Auth::isLoggedIn()) {
             self::jsonError("You must be logged in to perform this action", "NOT_AUTHENTICATED", 401);
             exit;
@@ -20,14 +19,14 @@ class ApiUtils {
     /**
      * Calls jsonResponse with true as success parameter
      */
-    public static function jsonSuccess($data = null, $code = null, $statusCode = null) {
+    public static function jsonSuccess($data = null, $code = null, ?int $statusCode = null): void {
         self::jsonResponse(true, $data, $code, $statusCode);
     }
 
     /**
      * Calls jsonResponse with false as success parameter
      */
-    public static function jsonError($data = null, $code = null, $statusCode = null) {
+    public static function jsonError($data = null, $code = null, ?int $statusCode = null): void {
         self::jsonResponse(false, $data, $code, $statusCode);
     }
 
@@ -42,11 +41,7 @@ class ApiUtils {
      * @param $code int|string error code
      * @param $statusCode int Status code to return. null to not change
      */
-    public static function jsonResponse($success, $data = null, $code = null, $statusCode = null) {
-        if (!is_bool($success)) {
-            throw new \InvalidArgumentException("success must be a boolean");
-        }
-
+    public static function jsonResponse(bool $success, $data = null, $code = null, ?int $statusCode = null): void {
         $json = ["success" => $success];
 
         if ($code !== null) {
@@ -68,16 +63,16 @@ class ApiUtils {
         self::outputJson($json);
     }
 
-    public static function outputJson($array) {
+    public static function outputJson(array $array): void {
         @header("Content-Type: application/json");
         echo json_encode($array);
     }
 
-    public static function getPostParam($key) {
+    public static function getPostParam(string $key) {
         return self::getParam($_POST, $key);
     }
 
-    public static function getGetParam($key) {
+    public static function getGetParam(string $key) {
         return self::getParam($_GET, $key);
     }
 
@@ -87,9 +82,9 @@ class ApiUtils {
      * @param $array array
      * @param $key string
      * @param $canBeArray bool whenever the data can be an array
-     * @return mixed
+     * @return string|array
      */
-    public static function getParam($array, $key, $canBeArray = false) {
+    public static function getParam(array $array, string $key, bool $canBeArray = false) {
         if (!isset($array[$key])) {
             self::jsonError("Parameter $key is not provided", 400);
             exit;
@@ -97,7 +92,7 @@ class ApiUtils {
 
         $data = $array[$key];
 
-        if (is_array($data) && !$canBeArray) {
+        if (!$canBeArray && is_array($data)) {
             self::jsonError("Parameter $key cannot be an array", 400);
             exit;
         }
diff --git a/src/private/php/Utils/DatabaseUtils.php b/src/private/php/Utils/DatabaseUtils.php
index 98d7b97..662ecdb 100644
--- a/src/private/php/Utils/DatabaseUtils.php
+++ b/src/private/php/Utils/DatabaseUtils.php
@@ -1,6 +1,7 @@
 <?php
 
 namespace Wruczek\TSWebsite\Utils;
+
 use Medoo\Medoo;
 use PDO;
 use Wruczek\TSWebsite\Config;
diff --git a/src/private/php/Utils/DateUtils.php b/src/private/php/Utils/DateUtils.php
index d7f13fa..fe4702a 100644
--- a/src/private/php/Utils/DateUtils.php
+++ b/src/private/php/Utils/DateUtils.php
@@ -11,7 +11,7 @@ class DateUtils {
      * be retrieved, default value is returned
      * @return string date format
      */
-    public static function getDateFormat() {
+    public static function getDateFormat(): string {
         try {
             return LanguageUtils::i()->translate("DATE_FORMAT");
         } catch (\Exception $e) {
@@ -24,7 +24,7 @@ class DateUtils {
      * be retrieved, default value is returned
      * @return string time format
      */
-    public static function getTimeFormat() {
+    public static function getTimeFormat(): string {
         try {
             return LanguageUtils::i()->translate("TIME_FORMAT");
         } catch (\Exception $e) {
@@ -34,29 +34,29 @@ class DateUtils {
 
     /**
      * Returns timestamp formatted to string with format from getDateFormat()
-     * @param $timestamp
+     * @param int $timestamp
      * @return false|string
      */
-    public static function formatDate($timestamp) {
+    public static function formatDate(int $timestamp) {
         return date(self::getDateFormat(), $timestamp);
     }
 
     /**
      * Returns timestamp formatted to string with format from getTimeFormat()
-     * @param $timestamp
+     * @param int $timestamp
      * @return false|string
      */
-    public static function foramtTime($timestamp) {
+    public static function foramtTime(int $timestamp) {
         return date(self::getTimeFormat(), $timestamp);
     }
 
     /**
      * Returns timestamp formatted with formatToDate() and formatToTime()
-     * @param $timestamp
+     * @param int $timestamp
      * @param string $additional additional date format
      * @return false|string
      */
-    public static function formatDatetime($timestamp, $additional = "") {
+    public static function formatDatetime(int $timestamp, string $additional = "") {
         return date(trim(self::getDateFormat() . ", " . self::getTimeFormat() . " " . $additional), $timestamp);
     }
 
diff --git a/src/private/php/Utils/Language/Language.php b/src/private/php/Utils/Language/Language.php
index b2a76d3..ed7b815 100644
--- a/src/private/php/Utils/Language/Language.php
+++ b/src/private/php/Utils/Language/Language.php
@@ -19,7 +19,7 @@ class Language {
      * @param $isDefault
      * @param $languageItems
      */
-    public function __construct($languageId, $languageNameEnglish, $languageNameNative, $languageCode, $isDefault, $languageItems) {
+    public function __construct(int $languageId, string $languageNameEnglish, string $languageNameNative, string $languageCode, bool $isDefault, array $languageItems) {
         $this->languageId = $languageId;
         $this->languageNameEnglish = $languageNameEnglish;
         $this->languageNameNative = $languageNameNative;
@@ -32,7 +32,7 @@ class Language {
      * Returns language ID
      * @return int language ID
      */
-    public function getLanguageId() {
+    public function getLanguageId(): int {
         return $this->languageId;
     }
 
@@ -40,7 +40,7 @@ class Language {
      * Returns language name in English
      * @return string language name in English
      */
-    public function getLanguageNameEnglish() {
+    public function getLanguageNameEnglish(): string {
         return $this->languageNameEnglish;
     }
 
@@ -48,7 +48,7 @@ class Language {
      * Returns language name in its native form
      * @return string language name in its native form
      */
-    public function getLanguageNameNative() {
+    public function getLanguageNameNative(): string {
         return $this->languageNameNative;
     }
 
@@ -56,7 +56,7 @@ class Language {
      * Returns language code
      * @return string language code
      */
-    public function getLanguageCode() {
+    public function getLanguageCode(): string {
         return $this->languageCode;
     }
 
@@ -64,7 +64,7 @@ class Language {
      * Returns true when this language is set as default site language
      * @return boolean true when default, false otherwise
      */
-    public function isDefault() {
+    public function isDefault(): bool {
         return $this->isDefault;
     }
 
@@ -72,7 +72,7 @@ class Language {
      * Sets this language as default language of the site
      * @return boolean true on success, false otherwise
      */
-    public function setAsDefaultLanguage() {
+    public function setAsDefaultLanguage(): bool {
         return LanguageUtils::i()->setDefaultLanguage($this);
     }
 
@@ -80,7 +80,7 @@ class Language {
      * Returns simple array with identifier -> value mapping, created from getLanguageItems()
      * @return array
      */
-    public function getSimpleItemsArray() {
+    public function getSimpleItemsArray(): array {
         $ret = [];
 
         foreach ($this->getLanguageItems() as $item) {
@@ -93,13 +93,15 @@ class Language {
     /**
      * Returns language item
      * @param $identifier string identifier
-     * @return LanguageItem LanguageItem if found, null otherwise
+     * @return LanguageItem|null LanguageItem if found, null otherwise
      */
-    public function getLanguageItem($identifier) {
+    public function getLanguageItem($identifier): ?LanguageItem {
         foreach ($this->getLanguageItems() as $item) {
-            if(strcasecmp($item->getIdentifier(), $identifier) === 0)
+            if(strcasecmp($item->getIdentifier(), $identifier) === 0) {
                 return $item;
+            }
         }
+
         return null;
     }
 
@@ -107,7 +109,7 @@ class Language {
      * Returns language strings
      * @return array array filled with LanguageItem
      */
-    public function getLanguageItems() {
+    public function getLanguageItems(): array {
         return $this->languageItems;
     }
 
diff --git a/src/private/php/Utils/Language/LanguageItem.php b/src/private/php/Utils/Language/LanguageItem.php
index 468e210..1856023 100644
--- a/src/private/php/Utils/Language/LanguageItem.php
+++ b/src/private/php/Utils/Language/LanguageItem.php
@@ -13,7 +13,7 @@ class LanguageItem {
      * @param $value
      * @param $comment
      */
-    public function __construct($identifier, $value, $comment) {
+    public function __construct(string $identifier, string $value, ?string $comment) {
         $this->identifier = $identifier;
         $this->value = $value;
         $this->comment = $comment;
@@ -23,7 +23,7 @@ class LanguageItem {
      * Returns item identifier
      * @return string
      */
-    public function getIdentifier() {
+    public function getIdentifier(): string {
         return $this->identifier;
     }
 
@@ -31,19 +31,19 @@ class LanguageItem {
      * Returns item value
      * @return string
      */
-    public function getValue() {
+    public function getValue(): string {
         return $this->value;
     }
 
     /**
      * Returns item comment, can be null
-     * @return string
+     * @return string|null
      */
-    public function getComment() {
+    public function getComment(): ?string {
         return $this->comment;
     }
 
-    public function __toString() {
+    public function __toString(): string {
         return $this->getValue();
     }
 
diff --git a/src/private/php/Utils/Language/LanguageUtils.php b/src/private/php/Utils/Language/LanguageUtils.php
index 00cefa5..791086c 100644
--- a/src/private/php/Utils/Language/LanguageUtils.php
+++ b/src/private/php/Utils/Language/LanguageUtils.php
@@ -21,8 +21,12 @@ class LanguageUtils {
 
     /**
      * Short function for translate
+     * @param string $identifier
+     * @param array|string $args
+     * @return string
+     * @throws \Exception
      */
-    public static function tl($identifier, $args = []) {
+    public static function tl(string $identifier, $args = []): string {
         return self::i()->translate($identifier, $args);
     }
 
@@ -37,47 +41,50 @@ class LanguageUtils {
     /**
      * Returns language by its ID
      * @param $languageId int Language ID
-     * @return Language|boolean returns Language when found, false otherwise
+     * @return Language|null returns Language when found, null otherwise
      */
-    public function getLanguageById($languageId) {
+    public function getLanguageById(int $languageId): ?Language {
         foreach ($this->getLanguages() as $lang) {
-            if($lang->getLanguageId() === $languageId)
+            if($lang->getLanguageId() === $languageId) {
                 return $lang;
+            }
         }
 
-        return false;
+        return null;
     }
 
     /**
      * Returns language by its Language Code
      * @param $languageCode string Language Code
-     * @return Language|boolean returns Language when found, false otherwise
+     * @return Language|null returns Language when found, null otherwise
      */
-    public function getLanguageByCode($languageCode) {
+    public function getLanguageByCode(string $languageCode): ?Language {
         foreach ($this->getLanguages() as $lang) {
-            if(strcasecmp($lang->getLanguageCode(), $languageCode) === 0)
+            if(strcasecmp($lang->getLanguageCode(), $languageCode) === 0) {
                 return $lang;
+            }
         }
 
-        return false;
+        return null;
     }
 
     /**
      * Returns all available languages
-     * @return array|mixed
+     * @return array
      */
-    public function getLanguages() {
+    public function getLanguages(): array {
         return $this->languages;
     }
 
     /**
      * Returns default language
-     * @return Language default language
+     * @return Language|null default language, null if not defined
      */
-    public function getDefaultLanguage() {
+    public function getDefaultLanguage(): ?Language {
         foreach ($this->getLanguages() as $lang) {
-            if($lang->isDefault())
+            if($lang->isDefault()) {
                 return $lang;
+            }
         }
 
         return null;
@@ -88,7 +95,7 @@ class LanguageUtils {
      * @param $language Language
      * @return boolean true on success, false otherwise
      */
-    public function setDefaultLanguage($language) {
+    public function setDefaultLanguage(Language $language): bool {
         $db = DatabaseUtils::i()->getDb();
 
         // set all languages as non-default, if this succeeds...
@@ -104,9 +111,9 @@ class LanguageUtils {
 
     /**
      * Tried to determine user language and returns it
-     * @return Language user language if determined, null otherwise
+     * @return Language|null user language if determined, null otherwise
      */
-    public function detectUserLanguage() {
+    public function detectUserLanguage(): ?Language {
         if (isset($_COOKIE["tswebsite_language"])) { // check cookie
             $langcode = $_COOKIE["tswebsite_language"];
         } else if (isset($_SERVER["HTTP_ACCEPT_LANGUAGE"])) { // check http headers
@@ -114,8 +121,9 @@ class LanguageUtils {
         }
 
         // if language with that code exists, return it
-        if(!empty($langcode) && ($lang = $this->getLanguageByCode($langcode)))
+        if(!empty($langcode) && ($lang = $this->getLanguageByCode($langcode))) {
             return $lang;
+        }
 
         return null;
     }
@@ -125,30 +133,49 @@ class LanguageUtils {
      * @param bool $updateCache true if the file cache should also be updated
      * @return array
      */
-    public function refreshLanguageCache($updateCache = true) {
+    public function refreshLanguageCache(bool $updateCache = true): array {
         $db = DatabaseUtils::i()->getDb();
-        $data = $db->select("languages", ["langid", "englishname", "nativename", "langcode", "isdefault"]);
+        $data = $db->select("languages", [
+            "langid",
+            "englishname",
+            "nativename",
+            "langcode",
+            "isdefault"
+        ]);
 
         $langs = [];
 
         foreach ($data as $lang) {
-            $langid = $lang["langid"];
+            $langid = (int) $lang["langid"];
             $englishname = $lang["englishname"];
             $nativename = $lang["nativename"];
             $langcode = $lang["langcode"];
-            $isdefault = $lang["isdefault"];
+            $isdefault = $lang["isdefault"] === "1";
 
-            $strings = $db->select("translations", ["identifier", "value", "comment"], ["langid" => $langid]);
+            $strings = $db->select("translations", [
+                "identifier",
+                "value",
+                "comment"
+            ], [
+                "langid" => $langid
+            ]);
 
             $languageItems = [];
 
-            foreach ($strings as $str)
-                $languageItems[] = new LanguageItem($str["identifier"], $str["value"], $str["comment"]);
+            foreach ($strings as $str) {
+                $comment = null;
+
+                if (isset($str["comment"]) && $str["comment"] !== "") {
+                    $comment = $str["comment"];
+                }
+
+                $languageItems[] = new LanguageItem($str["identifier"], $str["value"], $comment);
+            }
 
             $langs[] = new Language($langid, $englishname, $nativename, $langcode, $isdefault, $languageItems);
         }
 
-        uasort($langs, function ($a, $b) {
+        uasort($langs, function (Language $a, Language $b) {
             if ($a->getLanguageId() === $b->getLanguageId()) {
                 return 0;
             }
@@ -158,8 +185,9 @@ class LanguageUtils {
 
         $this->languages = $langs;
 
-        if($updateCache)
+        if($updateCache) {
             $this->cache->store("languages", $langs, Config::get("cache_languages", 300));
+        }
 
         return $langs;
     }
@@ -169,12 +197,12 @@ class LanguageUtils {
      * language, it tries to get it from the default language.
      * User language is determined with getDefaultLanguage() function.
      * @param $identifier string Translation identifier
-     * @param array $args Arguments that will replace placeholders
+     * @param array|string $args Arguments that will replace placeholders
      * @return string Translated text
      * @throws \Exception When default site or user language cannot
      * be found, and/or if $identifier is not found
      */
-    public function translate($identifier, $args = []) {
+    public function translate(string $identifier, $args = []): string {
         if (!is_array($args)) {
             $args = [$args];
         }
@@ -182,16 +210,19 @@ class LanguageUtils {
         $defaultlang = $this->getDefaultLanguage();
         $lang = $this->getLanguageById(@$_SESSION["userlanguageid"]);
 
-        if(!$lang && !$defaultlang)
+        if(!$lang && !$defaultlang) {
             throw new \Exception("Cannot get user or default language");
+        }
 
         $item = $lang->getLanguageItem($identifier);
 
-        if(!$item)
+        if(!$item) {
             $item = $defaultlang->getLanguageItem($identifier);
+        }
 
-        if(!$item)
+        if(!$item) {
             throw new \Exception("Cannot get translation for $identifier");
+        }
 
         $val = $item->getValue();
 
diff --git a/src/private/php/Utils/SingletonTait.php b/src/private/php/Utils/SingletonTait.php
index f868ac5..70c87d6 100644
--- a/src/private/php/Utils/SingletonTait.php
+++ b/src/private/php/Utils/SingletonTait.php
@@ -9,11 +9,12 @@ trait SingletonTait {
      * Call this method to get singleton
      * @return self
      */
-    public static function Instance() {
+    public static function Instance(): self {
         static $inst = null;
 
-        if ($inst === null)
+        if ($inst === null) {
             $inst = new self();
+        }
 
         return $inst;
     }
@@ -22,7 +23,7 @@ trait SingletonTait {
      * A shorthand to get the singleton
      * @return self
      */
-    public static function i() {
+    public static function i(): self {
         return self::Instance();
     }
 
diff --git a/src/private/php/Utils/TeamSpeakUtils.php b/src/private/php/Utils/TeamSpeakUtils.php
index 260f3b9..343a6f0 100644
--- a/src/private/php/Utils/TeamSpeakUtils.php
+++ b/src/private/php/Utils/TeamSpeakUtils.php
@@ -25,9 +25,9 @@ class TeamSpeakUtils {
     /**
      * Returns TeamSpeak3_Node_Host object created using
      * data from config database
-     * @return \TeamSpeak3_Node_Host
+     * @return \TeamSpeak3_Node_Host|null
      */
-    public function getTSNodeHost() {
+    public function getTSNodeHost(): ?\TeamSpeak3_Node_Host {
         if($this->tsNodeHost === null) {
             $hostname = $this->configUtils->getValue("query_hostname");
             $queryport = $this->configUtils->getValue("query_port");
@@ -49,9 +49,9 @@ class TeamSpeakUtils {
     /**
      * Returns TeamSpeak3_Node_Server object created
      * using getTSNodeHost() method.
-     * @return \TeamSpeak3_Node_Server
+     * @return \TeamSpeak3_Node_Server|null
      */
-    public function getTSNodeServer() {
+    public function getTSNodeServer(): ?\TeamSpeak3_Node_Server {
         // Don't continue if TSNodeHost is NULL (not working / not initialised)
         if($this->tsNodeServer === null && $this->getTSNodeHost()) {
             $port = $this->configUtils->getValue("tsserver_port");
@@ -92,15 +92,22 @@ class TeamSpeakUtils {
     /**
      * Tries to download file from the TS3 server. It might be an actual file,
      * icon or avatar. Returns downloaded data. Might throw exceptions when filetransfer fails.
-     * @param $filename
+     * @param string $filename
      * @param int $cid Channel Id (defaults to 0 - server)
      * @param string $cpw Channel password (defaults to empty)
-     * @return mixed
-     * @throws \TeamSpeak3_Adapter_ServerQuery_Exception
+     * @return \TeamSpeak3_Helper_String
+     * @throws \TeamSpeak3_Adapter_ServerQuery_Exception|\TeamSpeak3_Exception
      */
-    public function ftDownloadFile($filename, $cid = 0, $cpw = "") {
+    public function ftDownloadFile(string $filename, int $cid = 0, string $cpw = ""): \TeamSpeak3_Helper_String {
+        if (!$this->checkTSConnection()) {
+            throw new \TeamSpeak3_Exception("Cannot connect to the TeamSpeak server");
+        }
+
         $dl = $this->getTSNodeServer()->transferInitDownload(mt_rand(0x0000, 0xFFFF), $cid, $filename, $cpw);
+
+        // wrap host in brackets if it contains a colon (is a IPv6)
         $host = (false !== strpos($dl["host"], ":") ? "[" . $dl["host"] . "]" : $dl["host"]);
+
         $filetransfer = \TeamSpeak3::factory("filetransfer://$host:" . $dl["port"]);
 
         return $filetransfer->download($dl["ftkey"], $dl["size"]);
@@ -110,7 +117,7 @@ class TeamSpeakUtils {
      * Resets current connection, forces to reconnect to the TeamSpeak server
      * next time you call getTSNodeHost or getTSNodeServer
      */
-    public function reset() {
+    public function reset(): void {
         $this->tsNodeHost = null;
         $this->tsNodeServer = null;
     }
@@ -121,7 +128,7 @@ class TeamSpeakUtils {
      *          Use it just before accessing the server, preferably after checking cache.
      * @return bool true if TeamSpeak connection succeeded, false otherwise
      */
-    public function checkTSConnection() {
+    public function checkTSConnection(): bool {
         return $this->getTSNodeHost() !== null
             && $this->getTSNodeServer() !== null
             && empty($this->getExceptionsList());
@@ -131,7 +138,7 @@ class TeamSpeakUtils {
      * Adds exception to the exceptions list
      * @param \Exception $exception
      */
-    public function addExceptionToExceptionsList($exception) {
+    public function addExceptionToExceptionsList(\Exception $exception): void {
         $this->exceptionsList[$exception->getCode()] = $exception;
     }
 
@@ -140,7 +147,7 @@ class TeamSpeakUtils {
      * when calling getTSNodeServer(), getTSNodeServer() and other methods
      * @return array Array filled with exceptions. Empty if no exceptions where thrown.
      */
-    public function getExceptionsList() {
+    public function getExceptionsList(): array {
         return $this->exceptionsList;
     }
 }
diff --git a/src/private/php/Utils/TemplateUtils.php b/src/private/php/Utils/TemplateUtils.php
index 0a3bfc6..b2baac9 100644
--- a/src/private/php/Utils/TemplateUtils.php
+++ b/src/private/php/Utils/TemplateUtils.php
@@ -45,15 +45,16 @@ class TemplateUtils {
      * Returns latte object
      * @return \Latte\Engine Latte object
      */
-    public function getLatte() {
+    public function getLatte(): Engine {
         return $this->latte;
     }
 
     /**
      * Echoes rendered template
+     * @throws \Exception
      * @see renderTemplateToString
      */
-    public function renderTemplate($templateName, $data = [], $loadLangs = true) {
+    public function renderTemplate(string $templateName, array $data = [], bool $loadLangs = true): void {
         echo $this->renderTemplateToString($templateName, $data, $loadLangs);
     }
 
@@ -63,8 +64,13 @@ class TemplateUtils {
      * @param string $errorname Error title
      * @param string $description Error description
      */
-    public function renderErrorTemplate($errorcode = "", $errorname = "", $description = "") {
-        $data = ["errorcode" => $errorcode, "errorname" => $errorname, "description" => $description];
+    public function renderErrorTemplate(string $errorcode = null, string $errorname = "Error", string $description = null): void {
+        $data = [
+            "errorcode" => $errorcode,
+            "errorname" => $errorname,
+            "description" => $description
+        ];
+
         $this->renderTemplate("errorpage", $data, false);
     }
 
@@ -75,11 +81,16 @@ class TemplateUtils {
      * @return string Rendered template
      * @throws \Exception when we cannot get the CSRF token
      */
-    public function renderTemplateToString($templateName, $data = [], $loadLangs = true) {
+    public function renderTemplateToString($templateName, $data = [], $loadLangs = true): string {
         $dbutils = DatabaseUtils::i();
 
         if($loadLangs) {
-            $userlang = LanguageUtils::i()->getLanguageById($_SESSION["userlanguageid"]);
+            $langUtils = LanguageUtils::i();
+            $userlang = $langUtils->getLanguageById($_SESSION["userlanguageid"]);
+
+            if ($userlang === null) {
+                $userlang = $langUtils->getDefaultLanguage();
+            }
 
             $data["languageList"] = LanguageUtils::i()->getLanguages();
             $data["userLanguage"] = $userlang;
@@ -120,9 +131,9 @@ class TemplateUtils {
      * Returns time elapsed from website load start until now
      * @param bool $raw If true, returns elapsed time in
      * milliseconds. Defaults to false.
-     * @return string
+     * @return string|float
      */
-    public static function getRenderTime($raw = false) {
+    public static function getRenderTime(bool $raw = false) {
         if($raw) {
             return microtime(true) - __RENDER_START;
         } else {
@@ -136,16 +147,17 @@ class TemplateUtils {
      * @see getOldestCacheTimestamp
      * @param $data
      */
-    public function storeOldestCache($data) {
-        if ($data["expired"] && (!$this->oldestCache || $this->oldestCache > $data["time"]))
+    public function storeOldestCache($data): void {
+        if ($data["expired"] && (!$this->oldestCache || $this->oldestCache > $data["time"])) {
             $this->oldestCache = $data["time"];
+        }
     }
 
     /**
      * @see storeOldestCache
-     * @return int Oldest cache timestamp, null if not set
+     * @return int|null Oldest cache timestamp, null if not set
      */
-    public function getOldestCacheTimestamp() {
+    public function getOldestCacheTimestamp(): ?int {
         return $this->oldestCache;
     }
 
@@ -158,7 +170,7 @@ class TemplateUtils {
      *        resource and add a version timestamp. If string, its gonna treat it as a
      *        integrity hash and add it along with crossorigin="anonymous" tag.
      */
-    public static function includeResource($resourceType, $url, $parameter = null) {
+    public static function includeResource(string $resourceType, string $url, $parameter = null): void {
         $url = str_replace('{cdnjs}', 'https://cdnjs.cloudflare.com/ajax/libs', $url);
         $attributes = "";
 
@@ -185,14 +197,14 @@ class TemplateUtils {
     /**
      * @see includeResource
      */
-    public static function includeStylesheet($url, $parameter = null) {
+    public static function includeStylesheet(string $url, $parameter = null): void {
         self::includeResource("stylesheet", $url, $parameter);
     }
 
     /**
      * @see includeResource
      */
-    public static function includeScript($url, $parameter = null) {
+    public static function includeScript(string $url, $parameter = null): void {
         self::includeResource("script", $url, $parameter);
     }
 }
diff --git a/src/private/php/ViewerRenderer.php b/src/private/php/ViewerRenderer.php
index 728ae05..ab4a982 100644
--- a/src/private/php/ViewerRenderer.php
+++ b/src/private/php/ViewerRenderer.php
@@ -20,7 +20,7 @@ class ViewerRenderer {
 
     private $hiddenChannelIds;
 
-    public function __construct($imgPath, array $hiddenChannelIds = []) {
+    public function __construct(string $imgPath, array $hiddenChannelIds = []) {
         $this->imgPath = $imgPath;
         $this->hiddenChannelIds = $hiddenChannelIds;
 
diff --git a/src/private/php/load.php b/src/private/php/load.php
index 86683be..7e5cb7a 100644
--- a/src/private/php/load.php
+++ b/src/private/php/load.php
@@ -65,14 +65,14 @@ if(!isset($_SESSION["userlanguageid"])) {
     /**
      * Shortcut to translate and output the result
      */
-    function __($identifier, $args = []) {
+    function __(string $identifier, array $args = []) {
         echo __get($identifier, $args);
     }
 
     /**
      * Shortcut to translate and return the result
      */
-    function __get($identifier, $args = []) {
+    function __get(string $identifier, array $args = []) {
         try {
             return LanguageUtils::i()->translate($identifier, $args);
         } catch (\Exception $e) {